TWI879870B - Laser processing device and laser processing method - Google Patents

Abstract

The laser processing device includes a support part, an irradiation part, a moving mechanism, a driving part, a measurement data acquisition part, and a control part. The control part performs a first process and a second process. The first process is to move at least one of the support part and the irradiation part inwardly of the periphery of the object so that the focusing position moves along the periphery to form a first modified area inside the object along the periphery. The second process is to move at least one of the support part and the irradiation part so that the focusing position moves from the outside of the object to the inside after the first process to form a second modified area inside the object. The measurement data acquisition part associates the measurement data with the position information about the position of the object in the first process and acquires it. The control unit moves the position along the optical axis direction of at least one of the support unit of the driving unit and the focusing lens toward the initial position based on the measurement data obtained in the first processing before or when the focusing position enters the inside of the object from the outside in the second processing.

Description

Laser processing device and laser processing method

The present invention relates to a laser processing device and a laser processing method.

In the past, laser processing devices for forming a modified area on an object by irradiating the object with laser light are well known (for example, refer to Patent Document 1). Such a laser processing device comprises: a support portion for supporting the object; an irradiation portion for irradiating the object with laser light through a focusing lens; a moving mechanism for moving at least one of the support portion and the irradiation portion by moving the focusing position of the laser light; and a driving portion for driving the focusing lens along the optical axis direction by following the displacement of the laser light incident surface. [Prior Technical Document] [Patent Document]

[Patent Document 1] Japanese Patent Application Publication No. 2015-186825

[The problem the invention is trying to solve]

In the aforementioned technology, when the support part or the irradiation part is moved in such a way that the focusing position moves from the outside to the inside of the object to form a modified area on the object, there is a possibility that, for example, at a point in time just after the entry, an overshoot occurs in the control signal input to the drive part, thereby reducing the accuracy of the focusing lens in tracking the displacement of the laser light incident surface.

Therefore, the purpose of the present invention is to provide a laser processing device and a laser processing method that can suppress the reduction in the accuracy of the displacement of the laser light incident surface due to the tracking action. [Technical means to solve the problem]

A laser processing device according to one aspect of the present invention forms a modified area inside an object by irradiating the object with laser light, and is characterized by comprising: a support portion for supporting the object; an irradiation portion for irradiating the object with laser light through a focusing lens; a moving mechanism for moving at least one of the support portion and the irradiation portion to move the focusing position of the laser light; a driving portion for driving at least one of the support portion and the focusing lens along the optical axis direction of the focusing lens; a measurement data acquisition portion for acquiring measurement data on at least one of the displacement of the laser light incident surface of the object through which the laser light is incident and the displacement of the supporting surface of the support portion supporting the object; and a control portion for controlling the irradiation portion, the moving mechanism and the driving portion, wherein the control portion executes a first process and a second process. The first processing is to move at least one of the support part and the irradiation part in a manner that the focusing position moves along the periphery at a position further inward than the periphery of the object, thereby forming a first modified area inside the object along the periphery. The second processing is to move at least one of the support part and the irradiation part in a manner that the focusing position enters the inside of the object from the outside after the first processing, thereby forming a second modified area inside the object. The measurement data acquisition part associates and acquires the measurement data with the position information about the position of the object in the first processing. The control part moves the position along the optical axis direction of at least one of the support part and the focusing lens through the driving part toward the initial position according to the measurement data acquired in the first processing before or when the focusing position enters the inside of the object from the outside.

In this laser processing device, when the second process is performed, before or when the focusing position enters the inside of the object from the outside, the driving unit moves at least one of the support unit and the focusing lens toward the initial position based on the measurement data obtained in the first process. In this way, at a time point such as immediately after the entry, the aforementioned overshoot can be suppressed compared to a case where such an initial position is not considered. As a result, the accuracy of the displacement of the laser light incident surface by the tracking operation can be suppressed from being reduced.

In a laser processing device of one aspect of the present invention, the control unit may form a first modified region along a ring-shaped line around the periphery of the object in the first process, and form a second modified region along a straight line intersecting the ring-shaped line in the peripheral portion from the periphery of the object to the first modified region when viewed from the laser light incident surface in the second process. In this case, the peripheral portion of the object can be cut off and removed.

In one aspect of the present invention, the initial position of the laser processing device can be based on the position of the measured data, which is the measured data on the displacement of the intersection position of the ring line and the straight line on the laser light incident surface. In this way, when the peripheral part of the object is cut off and removed, the reduction in the accuracy of the displacement of the laser light incident surface by the tracking action can be further suppressed.

In one aspect of the laser processing device of the present invention, the control unit may be in the first processing, while moving at least one of the support unit and the irradiation unit in a manner that the focusing position moves along the periphery, and at the same time, the driving unit drives at least one of the support unit and the focusing lens in a manner that tracks the displacement of the laser light incident surface, and the measurement data acquisition unit may be in the first processing ... The control signal value of the driving unit when the driving unit drives at least one of the supporting unit and the focusing lens is used as the measurement data, and is associated with the position information and stored. The control unit reads the control signal value when the first processing tracks the displacement of the intersection position of the ring line and the first straight line, and moves at least one of the supporting unit and the irradiating unit along the first straight line to move the focusing lens. The light position enters the inside of the object from the outside, and a second modified area is formed in the peripheral part. Moreover, before the focusing position enters the inside of the object from the outside or enters the inside, the driving part is controlled by the read control signal value, so that at least one of the support part and the focusing lens moves toward the first initial position, and the control signal value at the time of displacement of the intersection position of the first processing tracking annular line and the second straight line is read, and at least one of the supporting part and the irradiation part is moved along the second straight line, so that the focusing position enters the inside of the object from the outside, and a second modified area is formed in the peripheral part. Moreover, before the focusing position enters the inside of the object from the outside or enters the inside, the driving part is controlled by the read control signal value, so that at least one of the supporting part and the focusing lens moves toward the second initial position. Thereby, when the peripheral portion of the object is cut off and removed, the reduction in the accuracy of the displacement of the laser light incident surface by the tracking operation can be further and specifically suppressed.

In a laser processing device of one aspect of the present invention, the control unit may form a first modified region along a ring-shaped line around the periphery of the object in the first process, and form a second modified region along a straight line intersecting the ring-shaped line in the inner portion of the object more inner than the first modified region when viewed from the laser light incident surface in the second process. In this case, the second modified region can be formed in the inner portion of the object so that the cracks formed from the second modified region are less likely to extend toward the peripheral portion of the object.

In a laser processing device of one aspect of the present invention, the initial position may be based on the position of the measured data, which is the measured data on the displacement of the intersection position of the ring line and the straight line on the laser light incident surface. In this way, when the second modified area is formed in a manner that makes it difficult for the tortoise crack from the second modified area to extend toward the peripheral portion, the reduction in the accuracy of the displacement of the laser light incident surface by the tracking action can be further suppressed.

In one aspect of the laser processing device of the present invention, the control unit may form a first modified area along a loop line around the periphery of the object in the first processing, and form a second modified area along an imaginary surface inside the object in the second processing. In this case, a peeling process can be achieved in which the object is peeled off along the imaginary surface.

In a laser processing device of one aspect of the present invention, the control unit may set the θ position around the θ axis of the laser light incident surface where the laser light is irradiated at the start of the second process as the θ position for the second process irradiation start, and the initial position is a position based on measurement data, and the measurement data is measurement data of the displacement of the θ position for the second process irradiation start of the ring line on the laser light incident surface. In this way, in the case of peeling processing in which the object is peeled along the imaginary surface, the reduction in the accuracy of the displacement of the laser light incident surface by the tracking action can be further suppressed.

In the laser processing device of one aspect of the present invention, the control unit may drive at least one of the support unit and the condensing lens to follow the displacement of the laser light incident surface by the driving unit after the condensing position is located at the peripheral portion from the periphery of the object to the first modified region when viewed from the laser light incident surface in the second process after the control unit moves at least one of the support unit and the condensing lens to the initial position. Even in such a manner, when the peripheral portion is driven to follow the displacement of the laser light incident surface, the reduction in the accuracy of the displacement of the laser light incident surface by the following operation can be suppressed.

In the laser processing apparatus of one aspect of the present invention, the control unit may move at least one of the support unit and the focusing lens to the initial position in the second process, and the driving unit may keep at least one of the support unit and the focusing lens at the initial position while the focusing position is located in the peripheral portion from the periphery of the object to the first modified region when viewed from the laser light incident surface. Even in this manner, when at least one of the support unit and the focusing lens is kept at the initial position in the peripheral portion, the reduction in the accuracy of the displacement of the laser light incident surface by the tracking operation can be suppressed.

In one aspect of the laser processing device of the present invention, the measurement data acquisition unit may include a sensor that irradiates the object with measurement light and detects information about reflected light of the measurement light reflected by the laser light incident surface. In this case, the measurement light may be used to cause at least one of the support unit and the focusing lens to track the displacement of the laser light incident surface.

A laser processing method according to one aspect of the present invention forms a modified region inside an object by irradiating a laser beam to the object, and is characterized by having: a first process, in which at least one of a support portion supporting the object and an irradiation portion irradiating the object with laser beam through a condensing lens is moved inwardly from the periphery of the object so that the focusing position of the laser beam moves along the periphery, thereby forming a first modified region inside the object along the periphery; and a second process, in which after the first process is performed, the support portion and the irradiation portion are moved in such a way that the focusing position moves from the outside of the object to the inside. At least one of the parts is moved to form a second modified area inside the object. In the first process, the displacement of the laser light incident surface of the object and the displacement of the supporting surface of the supporting part supporting the object are correlated with the position information about the position of the object and obtained. In the second process, before or when the focusing position enters the inside of the object from the outside, the position along the optical axis direction of at least one of the supporting part of the driving part and the focusing lens is moved toward the initial position according to the measurement data obtained in the first process.

In this laser processing method, when the second process is implemented, before or when the focusing position enters the interior of the object from the outside, the driving unit moves at least one of the support unit and the focusing lens toward the initial position based on the measurement data obtained in the first process. In this way, at a time point such as just after entering, the aforementioned overshoot can be suppressed compared to a case where such an initial position is not considered. As a result, the reduction in the accuracy of the displacement of the laser light incident surface by the tracking action can be suppressed. [Effect of the invention]

According to one aspect of the present invention, it is possible to provide a laser processing device and a laser processing method that can suppress a decrease in the accuracy of displacement of a laser light incident surface due to a tracking operation.

Hereinafter, the embodiments will be described in detail with reference to the drawings, etc. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and repeated descriptions will be omitted.

First, the basic structure, function, effect and modification examples of the laser processing device are explained.

[Structure of laser processing device] As shown in FIG. 1 , the laser processing device 1 has a plurality of moving mechanisms 5, 6; a support portion 7; a pair of laser processing heads 10A, 10B; a light source unit 8; and a control portion 9. In the following description, the first direction is referred to as the X direction, the second direction perpendicular to the first direction is referred to as the Y direction, and the third direction perpendicular to the first direction and the second direction is referred to as the Z direction. In this embodiment, the X direction and the Y direction are horizontal directions, and the Z direction is a vertical direction.

The moving mechanism 5 includes a fixed portion 51, a moving portion 53, and a mounting portion 55. The fixed portion 51 is mounted on the device frame 1a. The moving portion 53 is mounted on a track provided on the fixed portion 51 and is movable in the Y direction. The mounting portion 55 is mounted on a track provided on the moving portion 53 and is movable in the X direction.

The moving mechanism 6 has a fixed portion 61, a pair of moving portions 63, 64, and a pair of mounting portions 65, 66. The fixed portion 61 is mounted on the device frame 1a. The pair of moving portions 63, 64 are respectively mounted on rails provided on the fixed portion 61, and are each independently movable along the Y direction. The mounting portion 65 is mounted on the rail provided on the moving portion 63, and is movable along the Z direction. The mounting portion 66 is mounted on the rail provided on the moving portion 64, and is movable along the Z direction. That is, with respect to the device frame 1a, a pair of mounting portions 65, 66 are respectively movable along the Y direction and the Z direction. The moving portions 63, 64 constitute the first and second horizontal moving mechanisms (horizontal moving mechanisms), respectively. The mounting portions 65 and 66 constitute the first and second vertical movement mechanisms (vertical movement mechanisms), respectively.

The support part 7 is mounted on the rotation axis of the mounting part 55 provided on the moving mechanism 5, and can rotate with the axis parallel to the Z direction as the center line. That is, the support part 7 can move along the X direction and the Y direction respectively, and can rotate with the axis parallel to the Z direction as the center line. The support part 7 is used to support the object 100. The object 100 is, for example, a wafer.

As shown in FIG. 1 and FIG. 2 , the laser processing head 10A is mounted on the mounting portion 65 of the moving mechanism 6. The laser processing head 10A irradiates the object 100 supported by the support portion 7 with laser light L1 (also referred to as "first laser light L1") while being opposed to the support portion 7 in the Z direction. The laser processing head 10B is mounted on the mounting portion 66 of the moving mechanism 6. The laser processing head 10B irradiates the object 100 supported by the support portion 7 with laser light L2 (also referred to as "second laser light L2") while being opposed to the support portion 7 in the Z direction. The laser processing heads 10A and 10B constitute an irradiation portion.

The light source unit 8 has a pair of light sources 81 and 82. The light source 81 outputs laser light L1. The laser light L1 is emitted from the emission portion 81a of the light source 81 and guided to the laser processing head 10A through the optical fiber 2. The light source 82 outputs laser light L2. The laser light L2 is emitted from the emission portion 82a of the light source 82 and guided to the laser processing head 10B through the other optical fiber 2.

The control unit 9 is used to control the various parts of the laser processing device 1 (supporting unit 7, multiple moving mechanisms 5, 6, a pair of laser processing heads 10A, 10B, and light source unit 8, etc.). The control unit 9 is composed of a computer device including a processor, a memory, a storage, and a communication device. In the control unit 9, the software (program) loaded on the memory, etc. is executed by the processor, and the reading and writing of data in the memory and storage and the communication through the communication device are controlled by the processor. In this way, the control unit 9 can achieve various functions.

An example of processing performed by the laser processing apparatus 1 configured as above will be described. The example of processing is an example of forming a modified region inside the object 100 along a plurality of lines arranged in a grid shape in order to cut the object 100 as a wafer into a plurality of chips.

First, the moving mechanism 5 moves the support 7 in the X direction and the Y direction respectively, so that the support 7 supporting the object 100 faces the pair of laser processing heads 10A and 10B in the Z direction. Then, the moving mechanism 5 rotates the support 7 with an axis parallel to the Z direction as the center line, so that a plurality of lines extending in one direction on the object 100 are along the X direction.

Then, the moving mechanism 6 moves the laser processing head 10A along the Y direction so that the focal point (a part of the focal area) of the laser light L1 is located on a line extending in one direction. In addition, in order to make the focal point of the laser light L2 located on another line extending in one direction, the moving mechanism 6 moves the laser processing head 10B along the Y direction. Then, the moving mechanism 6 moves the laser processing head 10A along the Z direction so that the focal point of the laser light L1 is located inside the object 100. In addition, the moving mechanism 6 moves the laser processing head 10B along the Z direction so that the focal point of the laser light L2 is located inside the object 100.

Then, the light source 81 outputs the laser light L1 and the laser processing head 10A irradiates the laser light L1 to the object 100, and the light source 82 outputs the laser light L2 and the laser processing head 10B irradiates the laser light L2 to the object 100. At the same time, the moving mechanism 5 moves the support 7 along the X direction, so that the focal point of the laser light L1 moves relatively along the line extending in one direction, and the focal point of the laser light L2 moves relatively along other lines extending in one direction. In this way, the laser processing device 1 forms a modified area inside the object 100 along a plurality of lines extending in one direction in the object 100.

Next, the moving mechanism 5 rotates the support portion 7 with the axis parallel to the Z direction as the center line so that a plurality of lines extending in another direction perpendicular to the one direction on the object 100 are along the X direction.

Then, the moving mechanism 6 moves the laser processing head 10A along the Y direction so that the focal point of the laser light L1 is located on a line extending in another direction. In addition, in order to make the focal point of the laser light L2 located on another line extending in another direction, the moving mechanism 6 moves the laser processing head 10B along the Y direction. Then, the moving mechanism 6 moves the laser processing head 10A along the Z direction so that the focal point of the laser light L1 is located inside the object 100. In addition, the moving mechanism 6 moves the laser processing head 10B along the Z direction so that the focal point of the laser light L2 is located inside the object 100.

Then, the light source 81 outputs the laser light L1 and the laser processing head 10A irradiates the laser light L1 to the object 100, and the light source 82 outputs the laser light L2 and the laser processing head 10B irradiates the laser light L2 to the object 100. At the same time, the moving mechanism 5 moves the support 7 along the X direction, moves the focal point of the laser light L1 relatively along the line extending in the other direction, and moves the focal point of the laser light L2 relatively along other lines extending in the other direction. In this way, the laser processing device 1 forms a modified area inside the object 100 along a plurality of lines extending in another direction orthogonal to the one direction in the object 100.

Furthermore, in an example of the aforementioned processing, the light source 81 outputs a laser light L1 having transparency to the object 100 by, for example, a pulse oscillation method, and the light source 82 outputs a laser light L2 having transparency to the object 100 by, for example, a pulse oscillation method. If such laser light is focused inside the object 100, then the laser light is absorbed in the portion corresponding to the focal point of the laser light, and a modified region is formed inside the object 100. The modified region is a region whose density, refractive index, mechanical strength, other physical properties, etc. are different from the surrounding non-modified regions. The modified region includes, for example, a melt-processed region, a cracked region, an insulation-damaged region, a refractive index-changed region, and the like.

When the laser light output by pulse oscillation is irradiated to the object 100 and the focal point of the laser light is relatively moved along the line set on the object 100, a plurality of modified points are formed and arranged in a row along the line. One modified point is formed by irradiation of one pulse of laser light. One row of modified areas is a collection of a plurality of modified points arranged in one row. Adjacent modified points exist even in a connected or separated situation by the relative moving speed of the focal point of the laser light to the object 100 and the repetition frequency of the laser light. The shape of the set line is not limited to a grid shape, and can also be a ring shape, a straight line shape, a curve shape, and a combination of at least some of these shapes. [Structure of laser processing head]

As shown in FIG. 3 and FIG. 4 , the laser processing head 10A includes a housing 11 , an incident portion 12 , an adjustment portion 13 , and a focusing portion 14 .

The frame 11 has a first wall 21 and a second wall 22, a third wall 23 and a fourth wall 24, and a fifth wall 25 and a sixth wall 26. The first wall 21 and the second wall 22 are opposed to each other in the X direction. The third wall 23 and the fourth wall 24 are opposed to each other in the Y direction. The fifth wall 25 and the sixth wall 26 are opposed to each other in the Z direction.

The distance between the third wall portion 23 and the fourth wall portion 24 is smaller than the distance between the first wall portion 21 and the second wall portion 22. The distance between the first wall portion 21 and the second wall portion 22 is smaller than the distance between the fifth wall portion 25 and the sixth wall portion 26. Furthermore, the distance between the first wall portion 21 and the second wall portion 22 may be equal to the distance between the fifth wall portion 25 and the sixth wall portion 26, or may be larger than the distance between the fifth wall portion 25 and the sixth wall portion 26.

In the laser processing head 10A, the first wall portion 21 is located on the opposite side of the fixed portion 61 of the moving mechanism 6, and the second wall portion 22 is located on the fixed portion 61 side. The third wall portion 23 is located on the mounting portion 65 side of the moving mechanism 6, and the fourth wall portion 24 is located on the opposite side of the mounting portion 65, that is, on the laser processing head 10B side (see FIG. 2). The fifth wall portion 25 is located on the opposite side of the support portion 7, and the sixth wall portion 26 is located on the support portion 7 side.

The frame 11 is mounted on the mounting portion 65 when the third wall portion 23 is arranged on the mounting portion 65 side of the moving mechanism 6. Specifically, it is as follows. The mounting portion 65 has a seat plate 65a and a mounting plate 65b. The seat plate 65a is mounted on a rail provided on the moving portion 63 (refer to FIG. 2). The mounting plate 65b is erected on the end of the seat plate 65a on the laser processing head 10B side (refer to FIG. 2). The frame 11 is mounted on the mounting portion 65 by screwing the bolt 28 into the mounting plate 65b via the pedestal 27 when the third wall portion 23 contacts the mounting plate 65b. The pedestal 27 is provided on the first wall portion 21 and the second wall portion 22, respectively. The frame 11 can be loaded and unloaded with respect to the mounting portion 65.

The incident portion 12 is mounted on the fifth wall portion 25. The incident portion 12 injects the laser light L1 into the frame 11. The incident portion 12 is close to the second wall portion 22 side (one wall side) in the X direction and close to the fourth wall portion 24 side in the Y direction. That is, the distance between the incident portion 12 and the second wall portion 22 in the X direction is smaller than the distance between the incident portion 12 and the first wall portion 21 in the X direction, and the distance between the incident portion 12 and the fourth wall portion 24 in the Y direction is smaller than the distance between the incident portion 12 and the third wall portion 23 in the X direction.

The incident portion 12 is configured to be connectable to the connection end 2a of the optical fiber 2. The connection end 2a of the optical fiber 2 is provided with a collimating lens for collimating the laser light L1 emitted from the emission end of the optical fiber, and no isolator for suppressing the return light is provided. The isolator is provided near the optical fiber closer to the light source 81 side than the connection end 2a. In this way, the miniaturization of the connection end 2a can be sought, and the miniaturization of the incident portion 12 can be sought. Furthermore, the isolator can also be provided at the connection end 2a of the optical fiber 2.

The adjustment section 13 is disposed in the frame 11. The adjustment section 13 is used to adjust the laser light L1 incident from the incident section 12. The various structures of the adjustment section 13 are mounted on the optical base 29 provided in the frame 11. The optical base 29 is mounted on the frame 11 in such a manner that the area in the frame 11 is divided into an area on the side of the third wall 23 and an area on the side of the fourth wall 24. The optical base 29 is formed integrally with the frame 11. The various structures of the adjustment section 13 are mounted on the optical base 29 on the side of the fourth wall 24. The detailed description of the various structures of the adjustment section 13 will be described later.

The light-collecting portion 14 is mounted on the sixth wall portion 26. Specifically, the light-collecting portion 14 is arranged on the sixth wall portion 26 in a state of being inserted through a hole 26a formed in the sixth wall portion 26 (see FIG. 5). The light-collecting portion 14 collects the laser light L1 adjusted by the adjusting portion 13 and emits it out of the frame 11. The light-collecting portion 14 is close to the second wall portion 22 side (one wall side) in the X direction and close to the fourth wall portion 24 side in the Y direction. That is, the distance between the light-collecting portion 14 and the second wall portion 22 in the X direction is smaller than the distance between the light-collecting portion 14 and the first wall portion 21 in the X direction, and the distance between the light-collecting portion 14 and the fourth wall portion 24 in the Y direction is smaller than the distance between the light-collecting portion 14 and the third wall portion 23 in the X direction.

As shown in FIG5 , the adjustment section 13 has an attenuator 31, a beam expander 32, and a mirror 33. The incident section 12, and the attenuator 31, the beam expander 32, and the mirror 33 of the adjustment section 13 are arranged on a straight line (first straight line) A1 extending along the Z direction. The attenuator 31 and the beam expander 32 are arranged on the straight line A1 between the incident section 12 and the mirror 33. The attenuator 31 is used to adjust the output of the laser light L1 incident from the incident section 12. The beam expander 32 expands the diameter of the laser light L1 whose output is adjusted by the attenuator 31. The mirror 33 is used to reflect the laser light L1 whose diameter is expanded by the beam expander 32.

The adjustment section 13 also has a reflective spatial light modulator 34 and an imaging optical system 35. The reflective spatial light modulator 34 and the imaging optical system 35 of the adjustment section 13, and the focusing section 14 are arranged on a straight line (second straight line) A2 extending along the Z direction. The reflective spatial light modulator 34 modulates the laser light L1 reflected by the mirror 33. The reflective spatial light modulator 34 is, for example, a spatial light modulator (SLM: Spatial Light Modulator) of a reflective liquid crystal (LCOS: Liquid Crystal on Silicon). The imaging optical system 35 is a bilateral telecentric optical system in which the reflecting surface 34a of the reflective spatial light modulator 34 and the entrance pupil surface 14a of the focusing section 14 are in an imaging relationship. The imaging optical system 35 is composed of three or more lenses.

Straight line A1 and straight line A2 are located on a plane perpendicular to the Y direction. Straight line A1 is opposite to straight line A2 and is located on the second wall portion 22 side (the side of one wall portion). In the laser processing head 10A, the laser light L1 is incident from the incident portion 12 into the frame 11 and then travels on the straight line A1. After being reflected by the mirror 33 and the reflective spatial light modulator 34 in sequence, it travels on the straight line A2 and is emitted from the focusing portion 14 to the outside of the frame 11. Furthermore, the arrangement order of the attenuator 31 and the beam expander 32 may also be reversed. Furthermore, the attenuator 31 may also be arranged between the mirror 33 and the reflective spatial light modulator 34. Furthermore, the adjustment portion 13 may also have other optical components (for example, a turning mirror arranged in front of the beam expander 32).

The laser processing head 10A further includes a spectroscope 15 , a measuring unit 16 , an observation unit 17 , a driving unit 18 , and a circuit unit 19 .

The spectroscope 15 is disposed on the straight line A2 between the imaging optical system 35 and the focusing section 14. That is, the spectroscope 15 is disposed between the adjustment section 13 and the focusing section 14 in the frame 11. The spectroscope 15 is mounted on the optical base 29 on the side of the fourth wall section 24. The spectroscope 15 allows the laser light L1 to pass through. From the viewpoint of suppressing astigmatism, the spectroscope 15 may be, for example, a cubic shape or may be a two-plate type disposed in a twisted relationship.

The measuring unit 16 is arranged on the first wall 21 side (the side opposite to the wall side) with respect to the adjusting unit 13 in the frame 11. The measuring unit 16 is mounted on the optical base 29 on the fourth wall 24 side. The measuring unit 16 outputs a measuring light L10 for measuring the distance between the surface of the object 100 (for example, the surface on the side where the laser light L1 is incident) and the focusing unit 14, and detects the measuring light L10 reflected by the surface of the object 100 through the focusing unit 14. That is, the measuring light L10 output from the measuring unit 16 is irradiated to the surface of the object 100 through the focusing unit 14, and the measuring light L10 reflected by the surface of the object 100 is detected by the measuring unit 16 through the focusing unit 14.

More specifically, the measurement light L10 output from the measurement section 16 is reflected in sequence by the beam splitter 20 and the spectroscope 15 mounted on the optical base 29 on the side of the fourth wall 24, and then emitted from the focusing section 14 to the outside of the frame 11. The measurement light L10 reflected by the surface of the object 100 is incident from the focusing section 14 into the frame 11, and then reflected in sequence by the spectroscope 15 and the beam splitter 20, and then incident on the measurement section 16 and detected by the measurement section 16.

The observation section 17 is disposed on the first wall 21 side (the side opposite to the wall side) with respect to the adjustment section 13 in the frame 11. The observation section 17 is mounted on the optical base 29 on the fourth wall 24 side. The observation section 17 outputs the observation light L20 for observing the surface of the object 100 (for example, the surface on the side where the laser light L1 is incident), and detects the observation light L20 reflected by the surface of the object 100 through the focusing section 14. That is, the observation light L20 output from the observation section 17 is irradiated to the surface of the object 100 through the focusing section 14, and the observation light L20 reflected by the surface of the object 100 is detected by the observation section 17 through the focusing section 14.

More specifically, the observation light L20 output from the observation section 17 passes through the beam splitter 20, is reflected by the spectroscope 15, and is then emitted from the focusing section 14 to the outside of the frame 11. The observation light L20 reflected by the surface of the object 100 enters the frame 11 from the focusing section 14, is reflected by the spectroscope 15, and then passes through the beam splitter 20 to enter the observation section 17 and is detected by the observation section 17. Furthermore, the wavelengths of the laser light L1, the measurement light L10, and the observation light L20 are different from each other (at least the central wavelengths of each are offset from each other).

The driving unit 18 is mounted on the optical base 29 on the side of the fourth wall 24. The driving unit 18 moves the light collecting unit 14 disposed on the sixth wall 26 along the Z direction by the driving force of a piezoelectric element, for example.

The circuit section 19 is disposed in the frame 11 on the side of the third wall section 23 with respect to the optical base 29. That is, the circuit section 19 is disposed in the frame 11 on the side of the third wall section 23 with respect to the adjustment section 13, the measuring section 16, and the observation section 17. The circuit section 19 is, for example, a plurality of circuit substrates. The circuit section 19 processes the signal output from the measuring section 16 and the signal input to the reflective spatial light modulator 34. The circuit section 19 controls the driving section 18 according to the signal output from the measuring section 16. For example, the circuit section 19 controls the driving section 18 based on the signal output from the measuring section 16 so that the distance between the surface of the object 100 and the focusing section 14 is maintained constant (that is, the distance between the surface of the object 100 and the focusing point of the laser light L1 is maintained constant). Furthermore, the frame 11 is provided with a connector (not shown) for connecting wiring for electrically connecting the circuit section 19 to the control section 9 (see FIG. 1 ) and the like.

The laser processing head 10B is similar to the laser processing head 10A, and includes a housing 11, an incident portion 12, an adjustment portion 13, a focusing portion 14, a spectroscope 15, a measuring portion 16, an observation portion 17, a driving portion 18, and a circuit portion 19. However, the structures of the laser processing head 10B are arranged to have a plane-symmetrical relationship with the structures of the laser processing head 10A with respect to a virtual plane passing through the center point between a pair of mounting portions 65 and 66 and perpendicular to the Y direction, as shown in FIG.

For example, the frame (first frame) 11 of the laser machining head 10A is mounted on the mounting portion 65 in such a manner that the fourth wall portion 24 is located on the laser machining head 10B side with respect to the third wall portion 23, and the sixth wall portion 26 is located on the support portion 7 side with respect to the fifth wall portion 25. In contrast, the frame (second frame) 11 of the laser machining head 10B is mounted on the mounting portion 66 in such a manner that the fourth wall portion 24 is located on the laser machining head 10A side with respect to the third wall portion 23, and the sixth wall portion 26 is located on the support portion 7 side with respect to the fifth wall portion 25.

The frame 11 of the laser processing head 10B is configured to be mounted on the mounting portion 66 when the third wall portion 23 is arranged on the mounting portion 66 side. Specifically, it is as follows. The mounting portion 66 has a seat plate 66a and a mounting plate 66b. The seat plate 66a is mounted on a track provided on the moving portion 63. The mounting plate 66b is erected on the end of the seat plate 66a on the laser processing head 10A side. The frame 11 of the laser processing head 10B is mounted on the mounting portion 66 when the third wall portion 23 contacts the mounting plate 66b. The frame 11 of the laser processing head 10B can be loaded and unloaded on the mounting portion 66. [Function and Effect]

In the laser processing head 10A, since the light source for outputting the laser light L1 is not provided in the frame 11, the frame 11 can be miniaturized. In addition, in the frame 11, the distance between the third wall portion 23 and the fourth wall portion 24 is smaller than the distance between the first wall portion 21 and the second wall portion 22, and the light focusing portion 14 disposed on the sixth wall portion 26 is offset toward the fourth wall portion 24 in the Y direction. Thus, when the frame 11 is moved in a direction perpendicular to the optical axis of the light focusing portion 14, even if there is another component (such as the laser processing head 10B) on the fourth wall portion 24 side, the light focusing portion 14 can be brought close to the other component. Therefore, the laser processing head 10A can also move the light focusing portion 14 in a direction perpendicular to its optical axis.

In the laser processing head 10A, the incident portion 12 is provided on the fifth wall portion 25 and is offset in the Y direction toward the fourth wall portion 24. Thus, other components (such as the circuit portion 19) can be arranged in the region of the region within the frame 11 that is closer to the third wall portion 23 than the adjustment portion 13, and the region can be effectively utilized.

In the laser processing head 10A, the focusing part 14 is offset in the X direction toward the second wall part 22. Thus, when the frame 11 is moved in a direction perpendicular to the optical axis of the focusing part 14, even if there are other components on the second wall part 22, for example, the focusing part 14 can be brought close to the other components.

In the laser processing head 10A, the incident portion 12 is provided on the fifth wall portion 25 and is offset in the X direction toward the second wall portion 22. Thus, other components (such as the measuring portion 16 and the observation portion 17) can be arranged in the region of the region within the frame 11 that is closer to the first wall portion 21 than the adjustment portion 13, and the region can be effectively utilized.

Furthermore, in the laser processing head 10A, the measuring section 16 and the observation section 17 are arranged in the area inside the frame 11, on the side of the adjustment section 13 close to the first wall section 21, the circuit section 19 is arranged in the area inside the frame 11, on the side of the adjustment section 13 close to the third wall section 23, and the spectroscope 15 is arranged in the frame 11, between the adjustment section 13 and the focusing section 14. Thus, the area inside the frame 11 can be effectively used. Furthermore, in the laser processing device 1, processing can be performed based on the measurement result of the distance between the surface of the object 100 and the focusing section 14. Furthermore, in the laser processing device 1, processing can be performed based on the observation result of the surface of the object 100.

In the laser processing head 10A, the circuit section 19 controls the driving section 18 according to the signal output from the measuring section 16. Thus, the position of the focal point of the laser light L1 can be adjusted according to the measurement result of the distance between the surface of the object 100 and the focusing section 14.

In the laser processing head 10A, the incident part 12, the attenuator 31, the beam expander 32 and the mirror 33 of the adjustment part 13 are arranged on the straight line A1 extending along the Z direction, and the reflective spatial light modulator 34, the imaging optical system 35 and the focusing part 14 of the adjustment part 13, and the focusing part 14 are arranged on the straight line A2 extending along the Z direction. In this way, the adjustment part 13 having the attenuator 31, the beam expander 32, the reflective spatial light modulator 34 and the imaging optical system 35 can be compactly configured.

In the laser processing head 10A, the straight line A1 is opposite to the straight line A2 and is located on the second wall portion 22 side. Thus, in the region within the frame 11, other optical systems (such as the measuring section 16 and the observing section 17) using the focusing section 14 can be configured in the region closer to the first wall portion 21 than the adjusting section 13, and the degree of freedom of the structure of the other optical systems can be increased.

The above functions and effects can also be achieved by the laser processing head 10B.

In the laser processing device 1, the focusing portion 14 of the laser processing head 10A is offset toward the laser processing head 10B side at the frame 11 of the laser processing head 10A, and the focusing portion 14 of the laser processing head 10B is offset toward the laser processing head 10A side at the frame 11 of the laser processing head 10B. Thus, when the pair of laser processing heads 10A and 10B are moved in the Y direction, the focusing portion 14 of the laser processing head 10A and the focusing portion 14 of the laser processing head 10B can be brought close to each other. Therefore, according to the laser processing device 1, the object 100 can be processed efficiently.

Furthermore, in the laser processing device 1, the pair of mounting parts 65 and 66 can be moved in the Y direction and the Z direction, respectively. Thus, the object 100 can be processed more efficiently.

Furthermore, in the laser processing device 1, the support portion 7 can be moved in the X direction and the Y direction, respectively, and rotated with an axis parallel to the Z direction as the center line. Thus, the object 100 can be processed more efficiently. [Variation]

For example, as shown in FIG6 , the incident part 12, the adjustment part 13, and the focusing part 14 may be arranged on a straight line A extending along the Z direction. In this way, the adjustment part 13 can be compactly configured. In this case, the adjustment part 13 may not have the reflective spatial light modulator 34 and the imaging optical system 35. In addition, the adjustment part 13 may have the attenuator 31 and the beam expander 32. In this way, the adjustment part 13 having the attenuator 31 and the beam expander 32 can be compactly configured. Furthermore, the arrangement order of the attenuator 31 and the beam expander 32 may be reversed.

Furthermore, the frame 11 is configured such that at least one of the first wall portion 21, the second wall portion 22, the third wall portion 23, and the fifth wall portion 25 is disposed on the side of the mounting portion 65 (or the mounting portion 66) of the laser processing device 1, and the frame 11 can be mounted on the mounting portion 65 (or the mounting portion 66). Furthermore, the focusing portion 14 can be offset toward the fourth wall portion 24 at least in the Y direction. Thereby, when the frame 11 is moved along the Y direction, even if there are other components on the side of the fourth wall portion 24, for example, the focusing portion 14 can be brought close to the other components. Furthermore, when the frame 11 is moved along the Z direction, for example, the focusing portion 14 can be brought close to the object 100.

Furthermore, the light-collecting portion 14 may be offset toward the first wall portion 21 at least in the X direction. Thus, when the frame 11 is moved in a direction perpendicular to the optical axis of the light-collecting portion 14, even if there are other components on the first wall portion 21 side, for example, the light-collecting portion 14 can be brought close to the other components. In this case, the incident portion 12 may be offset toward the first wall portion 21 side in the X direction. Thus, other components (for example, the measuring portion 16 and the observing portion 17) can be arranged in the region within the frame 11 that is closer to the second wall portion 22 than the adjusting portion 13, and the region can be effectively utilized.

Furthermore, at least one of the guiding of the laser light L1 from the emitting portion 81a of the light source unit 8 to the incident portion 12 of the laser processing head 10A and the guiding of the laser light L2 from the emitting portion 82a of the light source unit 8 to the incident portion 12 of the laser processing head 10B may be implemented by a mirror. FIG7 is a front view of a portion of the laser processing device 1 in which the laser light L1 is guided by a mirror. In the structure shown in FIG7, the mirror 3 for reflecting the laser light L1 is mounted on the moving portion 63 of the moving mechanism 6 in such a manner as to be opposite to the emitting portion 81a of the light source unit 8 in the Y direction and to be opposite to the incident portion 12 of the laser processing head 10A in the Z direction.

In the structure shown in FIG. 7 , even if the moving portion 63 of the moving mechanism 6 is moved in the Y direction, the state in which the mirror 3 is opposed to the emission portion 81a of the light source unit 8 in the Y direction is maintained. Furthermore, even if the mounting portion 65 of the moving mechanism 6 is moved in the Z direction, the state in which the mirror 3 is opposed to the injection portion 12 of the laser processing head 10A in the Z direction is maintained. Therefore, the laser light L1 emitted from the emission portion 81a of the light source unit 8 can be reliably injected into the injection portion 12 of the laser processing head 10A without being affected by the position of the laser processing head 10A. In addition, a light source such as a high-output long and short pulse laser, which is extremely difficult to guide through the optical fiber 2, can also be used.

7, the mirror 3 may be mounted on the moving portion 63 of the moving mechanism 6 in a manner that allows at least one of angle adjustment and position adjustment. This allows the laser light L1 emitted from the emission portion 81a of the light source unit 8 to be more reliably emitted into the injection portion 12 of the laser processing head 10A.

Furthermore, the light source unit 8 may include one light source. In this case, the light source unit 8 may be configured to emit a portion of the laser light output from one light source from the emission portion 81a and to emit the remaining portion of the laser light from the emission portion 82b.

Furthermore, the laser processing device 1 may also include a laser processing head 10A. Even in the case of a laser processing device 1 including a laser processing head 10A, when the frame 11 is moved in the Y direction perpendicular to the optical axis of the focusing portion 14, even if there are other components on the side of the fourth wall portion 24, for example, the focusing portion 14 can be brought close to the other components. Therefore, according to the laser processing device 1 including a laser processing head 10A, the object 100 can be processed efficiently. Furthermore, in the laser processing device 1 including a laser processing head 10A, when the mounting portion 65 is moved in the Z direction, the object 100 can be processed efficiently. Furthermore, in the laser processing device 1 having one laser processing head 10A, if the support portion 7 moves in the X direction and rotates about an axis parallel to the Z direction as a center line, the object 100 can be processed more efficiently.

Furthermore, the laser processing device 1 may also have more than three laser processing heads. FIG8 is a perspective view of the laser processing device 1 having two pairs of laser processing heads. The laser processing device 1 shown in FIG8 has a plurality of moving mechanisms 200, 300, 400; a support portion 7; a pair of laser processing heads 10A, 10B; a pair of laser processing heads 10C, 10D; and a light source unit (not shown).

The moving mechanism 200 moves the support portion 7 in the X direction, the Y direction, and the Z direction, and rotates the support portion 7 with an axis parallel to the Z direction as a center line.

The moving mechanism 300 includes a fixed portion 301 and a pair of mounting portions (first mounting portion, second mounting portion) 305, 306. The fixed portion 301 is mounted on a device frame (not shown). The pair of mounting portions 305, 306 are mounted on rails provided on the fixed portion 301, and are independently movable in the Y direction.

The moving mechanism 400 has a fixed part 401 and a pair of mounting parts (first mounting part, second mounting part) 405, 406. The fixed part 401 is mounted on a device frame (not shown). The pair of mounting parts 405, 406 are respectively mounted on rails provided on the fixed part 401, and are independently movable along the X direction. Furthermore, the rails of the fixed part 401 are arranged to intersect with the rails of the fixed part 301 in a three-dimensional manner.

The laser processing head 10A is mounted on the mounting portion 305 of the moving mechanism 300. The laser processing head 10A irradiates the object 100 supported by the support portion 7 with laser light in a state where the laser processing head 10A is opposite to the support portion 7 in the Z direction. The laser light emitted from the laser processing head 10A is guided from the light source unit (not shown) by the optical fiber 2. The laser processing head 10B is mounted on the mounting portion 306 of the moving mechanism 300. The laser processing head 10B irradiates the object 100 supported by the support portion 7 with laser light in a state where the laser processing head 10B is opposite to the support portion 7 in the Z direction. The laser light emitted from the laser processing head 10B is guided from the light source unit (not shown) by the optical fiber 2.

The laser processing head 10C is mounted on the mounting portion 405 of the moving mechanism 400. The laser processing head 10C irradiates the object 100 supported by the support portion 7 with laser light in a state where the laser processing head 10C is opposite to the support portion 7 in the Z direction. The laser light emitted from the laser processing head 10C is guided from the light source unit (not shown) by the optical fiber 2. The laser processing head 10D is mounted on the mounting portion 406 of the moving mechanism 400. The laser processing head 10D irradiates the object 100 supported by the support portion 7 with laser light in a state where the laser processing head 10D is opposite to the support portion 7 in the Z direction. The laser light emitted from the laser processing head 10D is guided from the light source unit (not shown) by the optical fiber 2.

The structure of the pair of laser processing heads 10A and 10B of the laser processing device 1 shown in Fig. 8 is the same as the structure of the pair of laser processing heads 10A and 10B of the laser processing device 1 shown in Fig. 1. The structure of the pair of laser processing heads 10C and 10D of the laser processing device 1 shown in Fig. 8 is the same as the structure of the pair of laser processing heads 10A and 10B of the laser processing device 1 shown in Fig. 1 rotated 90 degrees with the axis parallel to the Z direction as the center line.

For example, the frame (first frame) 11 of the laser machining head 10C is mounted on the mounting portion 65 in such a manner that the fourth wall portion 24 is located on the laser machining head 10D side relative to the third wall portion 23, and the sixth wall portion 26 is located on the support portion 7 side relative to the fifth wall portion 25. In addition, the focusing portion 14 of the laser machining head 10C is offset in the Y direction toward the fourth wall portion 24 side (that is, the laser machining head 10D side).

The frame (second frame) 11 of the laser machining head 10D is mounted on the mounting portion 66 in such a manner that the fourth wall portion 24 is located on the laser machining head 10C side relative to the third wall portion 23, and the sixth wall portion 26 is located on the support portion 7 side relative to the fifth wall portion 25. In addition, the focusing portion 14 of the laser machining head 10D is offset in the Y direction toward the fourth wall portion 24 side (that is, the laser machining head 10C side).

As described above, in the laser processing device 1 shown in FIG8 , when the pair of laser processing heads 10A and 10B are moved in the Y direction, the focusing portion 14 of the laser processing head 10A and the focusing portion 14 of the laser processing head 10B can be brought close to each other. Also, when the pair of laser processing heads 10C and 10D are moved in the X direction, the focusing portion 14 of the laser processing head 10C and the focusing portion 14 of the laser processing head 10D can be brought close to each other.

Furthermore, the laser processing head and the laser processing device are not limited to those that form the modified region inside the object 100, and may also be those that perform other laser processing.

In the following description, the descriptions that are repeated with the above-mentioned embodiments are omitted.

The laser processing device 101 shown in FIG9 is a device that forms a modified area on the object 100 by irradiating laser light toward the object 100 in accordance with the focusing position (at least a part of the focusing area, the focusing point). The laser processing device 101 performs trimming processing, radial cutting processing, and stripping processing on the object 100 to obtain (manufacture) a semiconductor device. The trimming processing is a processing for removing an unnecessary portion of the object 100. The radial cutting processing is a processing for separating the unnecessary portion removed by the trimming processing. The stripping processing is a processing for stripping a part of the object 100.

The object 100 includes, for example, a semiconductor wafer formed in a disk shape. The object is not particularly limited and may be formed of various materials and may have various shapes. A functional element (not shown) is formed on the surface 100a of the object 100. The functional element is, for example, a light-receiving element such as a light-emitting diode, a light-emitting element such as a laser diode, a circuit element such as a memory, and the like.

As shown in FIG. 10( a) and FIG. 10( b), an effective area R and a removal area E are set in the object 100. The effective area R is a portion corresponding to the semiconductor device to be obtained. The effective area R is a device area. For example, the effective area R is a disk-shaped portion including the central portion when the object 100 is viewed from the thickness direction. The effective area R is an inner area that is further inward than the removal area E. The removal area E is an area further outward than the effective area R of the object 100. The removal area E is an outer edge portion outside the effective area R in the object 100. For example, the removal area E is a ring-shaped portion surrounding the effective area R. The removal area E includes the peripheral portion (the beveled portion of the outer edge) when the object 100 is viewed from the thickness direction. The removal area E is a radial cutting area that becomes the object of radial cutting processing.

In the object 100, a virtual surface M1 is set as a surface predetermined for peeling. The virtual surface M1 is a surface predetermined to form a modified area by peeling processing. The virtual surface M1 is a surface opposite to the laser light incident surface of the object 100, that is, the back side 100b. The virtual surface M1 is a surface parallel to the back side 100b, and is, for example, circular. The virtual surface M1 is a virtual area, which is not limited to a plane, and can also be a curved surface or even a three-dimensional surface. The setting of the effective area R, the removal area E and the virtual surface M1 can be performed in the control unit 9. The effective area R, the removal area E and the virtual surface M1 can also be specified by coordinates.

In the object 100, a line (annular line) M2 is set as a predetermined trimming line. The line M2 is a line for forming a modified area predetermined to be processed by trimming. The line M2 extends in a ring shape inside the outer edge of the object 100. Here, the line M2 extends in a circular ring shape. The line M2 is set at the boundary between the effective area R and the removal area E in the part of the interior of the object 100 that is closer to the opposite side of the laser light incident surface than the imaginary surface M1. The setting of the line M2 can be performed in the control unit 9. The line M2 is an imaginary line, but it can also be a line actually drawn. The line M2 can also be specified by coordinates. The description of the setting of the line M2 is the same as that of the lines M3 to M5 described later.

In the object 100, a line (straight line) M3 is set as a predetermined radial cutting line. The line M3 is a line for forming a modified area predetermined to be processed by radial cutting. The line M3 extends in a straight line (radial) along the radial direction of the object 100 when viewed from the laser light incident surface. When viewed from the laser light incident surface, a plurality of lines M3 are provided in a manner that the removal area E is equally divided in the circumferential direction (four divisions in this case). In the example shown in the figure, the line M3 includes lines M3a and M3b extending in one direction when viewed from the laser light incident surface; and lines M3c and M3d extending in another direction orthogonal to the one direction.

As shown in FIG9 , the laser processing device 101 includes a stage 107, a laser processing head 10A, a first Z-axis track 106A, a Y-axis track 108, an imaging unit 110, a GUI (Graphical User Interface) 111, and a control unit 9. The stage 107 is a support unit for supporting the object 100. The stage 107 is configured in the same manner as the support unit 7 (see FIG1 ). The object 100 is placed on a support surface 107a of the stage 107 in a state where the back side 100b of the object 100 is set as the laser light incident side, i.e., the upper side (the surface 100a is set as the stage 107 side, i.e., the lower side). The stage 107 has a rotation axis C provided at its center. The rotation axis C is an axis extending along the optical axis direction of the light focusing unit 14, that is, the Z direction. The mounting table 107 can rotate around the rotation axis C. The mounting table 107 is rotationally driven by a driving force of a conventional driving device such as a motor.

The laser processing head 10A irradiates the object 100 placed on the mounting table 107 with laser light L1 along the Z direction via the focusing portion 14 (refer to FIG. 11(a)), thereby forming a modified area inside the object 100. The laser processing head 10A is mounted on the first Z-axis track 106A and the Y-axis track 108. The laser processing head 10A can be moved linearly in the Z direction along the first Z-axis track 106A by the driving force of a known driving device such as a motor. The laser processing head 10A can be moved linearly in the Y direction along the Y-axis track 108 by the driving force of a known driving device such as a motor. The laser processing head 10A constitutes an irradiation portion. The light-collecting unit 14 includes a light-collecting lens.

The laser processing head 10A is equipped with: a reflective spatial light modulator 34, a drive unit 18 and a distance measuring sensor 36. The reflective spatial light modulator 34 and the drive unit 18 have the aforementioned structure (refer to FIG. 5). The distance measuring sensor 36 is a sensor for reflecting the distance measuring laser light (measurement light) reflected by the laser light incident surface of the object 100 when the distance measuring laser light (measurement light) is irradiated on the laser light incident surface of the object 100. The distance measuring sensor 36 obtains information about the received reflected light as displacement data about the displacement (including convexity and concavity, tilt, etc.) of the laser light incident surface of the object 100. The displacement data is, for example, a voltage value corresponding to the received reflected light. When the distance measuring sensor 36 is a sensor that is not coaxial with the laser light L1, a sensor of a triangular distance measuring method, a laser confocal method, a white confocal method, a spectral interference method, an astigmatism method, etc. can be used. When the distance measuring sensor 36 is a sensor that is coaxial with the laser light L1, a sensor of an astigmatism method, etc. can be used. The type of the distance measuring sensor 36 is not particularly limited, and various sensors can be used.

The circuit section 19 (see FIG. 3 ) of the laser processing head 10A drives the driving section 18 (see FIG. 5 ) based on the displacement data obtained by the distance measuring sensor 36 so that the focusing section 14 follows the laser light incident surface. For example, the driving section 18 drives the focusing section 14 in the Z direction in such a manner that the voltage value obtained as the displacement data is obtained by the distance measuring sensor 36 and the obtained voltage value is used as a reference value. The reference value is a voltage value that serves as a reference for driving the focusing section 14 to follow the laser light irradiation surface, that is, a height setting voltage value when setting the height described later. Hereinafter, driving the focusing unit 14 to track the laser light irradiation surface is referred to as AF (auto focus) tracking.

Thus, the focusing unit 14 is moved along the Z direction according to the displacement data, and the distance between the laser light incident surface of the object 100 and the focusing position of the laser light L1 is maintained constant. The circuit unit 19 stores (acquires) the control signal value of the driving unit 18 in a manner that the focusing unit 14 follows the laser light incident surface as measurement data. The distance measurement sensor 36 and the circuit unit 19 constitute a measurement data acquisition unit. Furthermore, the control unit 9 or other circuit units may have the function of following and driving the driving unit 18 and the function of storing the control signal value. The measurement data obtained in the above manner is not only about the displacement of the laser light incident surface of the object 100, but also about the displacement of the support surface 107a supporting the object 100. Incidentally, the measurement data only need to be about at least one of the displacement of the laser light incident surface and the displacement of the support surface 107a, and such measurement data can be obtained by various known techniques.

The first Z-axis track 106A is a track extending along the Z direction. The first Z-axis track 106A is mounted on the laser processing head 10A via the mounting portion 65. The first Z-axis track 106A moves the laser processing head 10A along the Z direction, and moves the focusing position of the laser light L1 along the Z direction (the direction intersecting the imaginary plane M1). The Y-axis track 108 is a track extending along the Y direction. The Y-axis track 108 is mounted on the first Z-axis track 106A. The Y-axis track 108 moves the laser processing head 10A along the Y direction, and moves the focusing position of the laser light L1 along the Y direction (the direction along the imaginary plane M1). The first Z-axis track 106A and the Y-axis track 108 correspond to the tracks of the aforementioned moving mechanism 6 (see FIG. 1 ) or the aforementioned moving mechanism 300 (see FIG. 8 ). The first Z-axis track 106A and the Y-axis track 108 are used to move the focusing position of the laser light L1 by the focusing unit 14, so as to move at least one of the mounting table 107 and the laser processing head 10A. Hereinafter, the focusing position of the laser light L1 by the focusing unit 14 is also referred to as the “focusing position”.

The imaging unit 110 captures the object 100 from a direction along the incident direction of the laser light L1. The imaging unit 110 includes an alignment camera AC and an imaging unit IR. The alignment camera AC and the imaging unit IR are mounted on the mounting portion 65 together with the laser processing head 10A. The alignment camera AC captures the device pattern, etc., using light that has passed through the object 100. The image thus obtained is provided for alignment of the irradiation position of the laser light L1 on the object 100.

The imaging unit IR captures an image of the object 100 by light passing through the object 100. For example, when the object 100 is a wafer including silicon, the imaging unit IR uses light in the near-infrared region. The imaging unit IR has a light source, an objective lens, and a light detection unit. The light source outputs light that is transparent to the object 100. The light source is composed of, for example, a halogen lamp and a filter, and outputs light in the near-infrared region. The light output from the light source is guided by an optical system such as a mirror and passes through the objective lens, and then irradiates the object 100. The objective lens allows light reflected from the surface opposite to the laser light incident surface of the object 100 to pass through. That is, the objective lens allows light that propagates (transmits) the object 100 to pass through. The objective lens has a correction ring. The correction ring corrects the aberration generated in the light in the object 100, for example, by adjusting the distance between the plurality of lenses constituting the objective lens. The light detection unit detects the light that passes through the objective lens. The light detection unit is constituted by, for example, an InGaAs camera, and detects light in the near-infrared region. The imaging unit IR can photograph at least one of the modified area formed inside the object 100 and the cracks extending from the modified area. In the laser processing device 101, the imaging unit IR can be used to confirm the processing status of the laser processing in a non-destructive manner.

The GUI 111 displays various information. The GUI 111 includes, for example, a touch panel display. The GUI 111 allows the user to input various settings related to processing conditions through touch, etc. The GUI 111 constitutes an input unit that receives input from the user.

The control unit 9 is constituted as a computer device including a processor, a memory, a storage, and a communication device. In the control unit 9, the software (program) loaded on the memory, etc. is executed by the processor, and the reading and writing of data in the memory and the storage and the communication through the communication device are controlled by the processor. The control unit 9 controls each part of the laser processing device 101 to achieve various functions.

The control unit 9 controls at least: the stage 107, the laser processing head 10A, and the aforementioned moving mechanism 6 (refer to FIG. 1 ) or the aforementioned moving mechanism 300 (refer to FIG. 1 ). The control unit 9 controls the rotation of the stage 107, the irradiation of the laser light L1 from the laser processing head 10A, and the movement of the focusing position of the laser light L1. The control unit 9 can perform various controls based on the rotation information about the rotation amount of the stage 107 (hereinafter also referred to as [θ information]). The θ information can be obtained from the driving amount of the driving device that rotates the stage 107, and can also be obtained by other sensors, etc. The θ information can be obtained by various known methods.

The control unit 9 controls the start and stop of irradiation of the laser light L1 of the laser processing head 10A according to the θ information while rotating the stage 107 so that the focusing position is located on the line M2 (the periphery of the effective area R) of the object 100, and performs a trimming process to form a modified area along the periphery of the effective area R. The trimming process is a process of the control unit 9 that realizes the trimming process.

The control unit 9 controls the start and stop of the irradiation of the laser light L1 of the laser processing head 10A without rotating the stage 107, and moves the focusing position of the laser light L1 along the line M3, thereby performing the radial cutting process to form the modified area in the removal area E along the line M3. The radial cutting process is the process of the control unit 9 to realize the radial cutting process.

The control unit 9 performs a peeling process to form a modified area along the imaginary surface M1 inside the object 100 by rotating the stage 107 while irradiating the laser light L1 from the laser processing head 10A and controlling the movement of the focusing position in the Y direction. The peeling process is a process of the control unit 9 to realize the peeling process. The control unit 9 controls the display of the GUI 111. According to various settings input from the GUI 111, the trimming process, the radial cutting process and the peeling process are performed.

The switching of the formation of the modified region and the stopping thereof can be achieved in the following manner. For example, in the laser processing head 10A, by switching the start and stop (ON/OFF) of the irradiation (output) of the laser light L1, the formation of the modified region and the stopping of the formation can be switched. Specifically, in the case where the laser oscillator is composed of a solid laser, the start and stop of the irradiation of the laser light L1 are switched at high speed by switching the ON/OFF of the Q switch (AOM (acoustic optical modulator), EOM (electro-optical modulator), etc.) provided in the resonator. In the case where the laser oscillator is composed of an optical fiber laser, the start and stop of the irradiation of the laser light L1 are switched at high speed by switching the ON/OFF of the output of the seed laser and the semiconductor laser constituting the amplifier (excitation) laser. When the laser oscillator uses an external modulation element, the irradiation of the laser light L1 is switched ON/OFF at high speed by switching the external modulation element (AOM, EOM, etc.) provided outside the resonator ON/OFF.

Alternatively, the switching between the formation of the modified area and its stopping can also be achieved in the following manner. For example, the formation of the modified area and the stopping of the formation can be switched by controlling a mechanical mechanism such as a shutter to open and close the optical path of the laser light L1. The formation of the modified area can also be stopped by switching the laser light L1 to CW light (continuous wave). The formation of the modified area can also be stopped by displaying a pattern that is made to be in a state that cannot modify the focusing state of the laser light L1 (for example, a satin pattern that scatters the laser light) on the liquid crystal layer of the reflective spatial light modulator 34. The formation of the modified area can also be stopped by controlling the output adjustment unit such as an attenuator to reduce the output of the laser light L1 to the point where the modified area cannot be formed. The formation of the modified region can also be stopped by switching the polarization direction. The formation of the modified region can also be stopped by scattering (scattering) the laser light L1 in directions other than the optical axis to cut it off.

Next, an example of a laser processing method for obtaining (manufacturing) a semiconductor device by performing trimming processing, radial cutting processing, and stripping processing on the object 100 using the laser processing device 101 will be described below.

First, the object 100 is placed on the mounting table 107 with the back surface 100b being the laser light incident side. The surface 100a of the object 100 on which the functional element is mounted is adhered to a supporting substrate or a tape member for protection.

Next, the trimming process is performed. In the trimming process, the trimming process (first process) is executed by the control unit 9. The trimming process includes a trimming process (first process). Specifically, in the trimming process, as shown in FIG. 11(a), while the stage 107 is rotated at a certain rotation speed, the focusing position P1 is located on the line M2, and the irradiation start and stop of the laser light L1 of the laser processing head 10A is controlled according to the θ information. Thereby, as shown in FIG. 11(b) and FIG. 11(c), a modified area 4 is formed along the line M2. The formed modified area 4 includes a modified point and a crack extending from the modified point.

Next, radial cutting processing is performed. In radial cutting processing, the control unit 9 executes radial cutting processing (second processing). Radial cutting processing includes a radial cutting process (second process). Specifically, in radial cutting processing, as shown in Figures 11(b) and 12(a), the laser processing head 10A irradiates laser light L1 without rotating the stage 107, and the laser processing head 10A is moved along the Y-axis track 108 so that the focusing position P1 moves along the lines M3a and M3b. After rotating the stage 107 90 degrees, the laser processing head 10A irradiates laser light L1 without rotating the stage 107, and the laser processing head 10A is moved along the Y-axis track 108 so that the focusing position P1 moves along the lines M3c and M3d. Thus, as shown in FIG. 12( b ), a modified region 4 is formed along the line M3. The formed modified region 4 includes a modified point and a crack extending from the modified point. The crack may reach at least one of the surface 100a and the back surface 100b, or may not reach at least one of the surface 100a and the back surface 100b. Then, as shown in FIG. 13( a ) and FIG. 13( b ), the removal region E is cut off and removed with the modified region 4 as a boundary, for example, by a jig or air.

Next, the peeling process is performed. Specifically, as shown in FIG13(c), while the stage 107 is rotated at a certain rotation speed, the laser light L1 is irradiated from the laser processing head 10A, and the laser processing head 10A is moved along the Y-axis track 108, so that the focusing position P1 moves from the outer edge side of the imaginary surface M1 to the inner side, along the Y direction. Thereby, as shown in FIG13(a) and FIG13(b), a modified area 4 extending in a spiral shape (asymptotic line) centered on the position of the rotation axis C (see FIG9) is formed inside the object 100 along the imaginary surface M1. The formed modified area 4 includes a plurality of modified points.

Next, as shown in FIG14(c), a portion of the object 100 is peeled off by, for example, an adsorption jig, with the modified region 4 covering the imaginary surface M1 as the boundary. The peeling of the object 100 can be carried out on the mounting table 107, or it can be moved to an area dedicated to peeling. The peeling of the object 100 can also be carried out by using air blowing or a tape. In the case where the object 100 cannot be peeled off by external stress alone, the modified region 4 can be selectively etched by an etching liquid (KOH or TMAH, etc.) that reacts with the object 100. In this way, the object 100 can be easily peeled off. As shown in FIG. 14( d ), the peeled surface 100h of the object 100 is finely ground or polished with a grinding material KM such as a grindstone. In the case where the object 100 is peeled off by etching, the polishing can also be simplified. As a result of the above, a semiconductor device 100K is obtained.

Next, the trimming process and radial cutting process are explained in detail.

First, based on the image of the laser light incident surface of the object 100 obtained by the imaging unit 110, for example, the laser processing head 10A is moved in the Z direction by the control unit 9 so that the focusing position is located on the laser light incident surface, and the focusing unit 14 is moved in the Z direction. Hereinafter, the alignment of the focusing unit 14 to the laser light incident surface is referred to as height setting, and the position of the focusing unit 14 at this time is referred to as the height position. In the height setting, the focusing position can be aligned with the center Ct of the laser light incident surface, or the focusing position can be aligned with the trimming line M3.

Next, the laser processing head 10A is moved in the Z direction by the control unit 9 so that the focusing position is located at the trimming depth (the depth of the modified area 4 formed by the trimming process) from the laser light incident surface, and the focusing unit 14 is moved in the Z direction from the height setting position by a distance corresponding to the trimming depth. At this time, the voltage value obtained by the distance measurement sensor 36 is stored as a reference voltage value for trimming. Next, the laser processing head 10A is moved in the Z direction by the control unit 9 so that the focusing position is located at the radial cutting depth (the depth of the modified area 4 formed by the radial cutting process) from the laser light incident surface, and the focusing unit 14 is moved in the Z direction from the height setting position by a distance corresponding to the radial cutting process. At this time, the voltage value obtained by the distance measuring sensor 36 is stored as a reference voltage value for radial cutting.

Next, as shown in FIG. 15( b ), the control unit 9 performs trimming processing (trimming process) to move the laser processing head 10A in a manner that the focusing position moves along the line M2 further inward than the periphery of the object 100, thereby forming a first modified area 41 along the line M3 inside the object 100.

In the trimming process, the laser processing head 10A is moved so that the focusing position moves along the line M2, and the voltage value obtained by the distance measurement sensor 36 becomes a reference voltage value for trimming. The driving unit 18 is driven by the circuit unit 19 to follow the displacement of the laser light incident surface, and AF tracking of driving the focusing unit 14 is performed. In addition, the control signal value of the driving unit 18 that realizes the AF tracking, that is, the measurement data, is correlated with the position information of the object 100 (here, the θ position) by the circuit unit 19 and is obtained. At the θ position in the figure, when viewing the object 100 from the laser light incident surface, one direction is the 12 o'clock direction, the direction 90° from the 12 o'clock direction in the clockwise direction is the 3 o'clock direction, the direction 90° from the 3 o'clock direction in the clockwise direction is the 6 o'clock direction, and the direction 90° from the 6 o'clock direction in the clockwise direction is the 9 o'clock direction.

FIG. 16 is a graph showing an example of measurement data associated with the θ position. As shown in the example of FIG. 16, the measurement data can be displayed by a graph with the θ position of the object 100 as the horizontal axis and the measurement data as the vertical axis. The measurement data is stored in the control unit 9 or the circuit unit 19. Furthermore, in the AF tracking of the case where a plurality of rows of the first modified regions 41 are formed on the line M2, the measurement data can be stored when the first modified region 41 of the first row is formed, and the measurement data can be used when the first modified regions 41 of the second row and below are formed. When the position of the first modified area 41 in the Z direction does not reach the measurement range of AF tracking, AF tracking can be performed after the focusing position is initially aligned with the measurement range (e.g., the laser light incident surface), and then the measurement data is stored and used to form the first modified area 41. This is also the case in the following AF tracking.

Next, as shown in FIG. 15( b) and FIG. 17 , after the trimming process, the control unit 9 performs the radial cutting process, and moves the laser processing head 10A along the lines M3a to M3d in such a manner that the focusing position enters from the outside to the inside of the object 100 and exits from the inside to the outside. Thus, a second modified area 42 is formed inside the removal area E of the object 100 along the lines M3a to M3d.

In the radial cutting process, before or when the focusing position enters the object 100 from the outside to the inside, the position of the focusing unit 14 along the Z direction is moved by the driving unit 18 to the initial position based on the measurement data obtained in the trimming process. The initial position is a position based on the measurement data of the intersection position of the line M2 and the lines M3a and M3c on the laser light incident surface. In the radial cutting process, after the focusing unit 14 is moved to the initial position, when the focusing position is located at the removal area E, the laser processing head 10A is moved in such a manner that the focusing position moves along the line M3, while the driving unit 18 performs AF tracking.

Specifically, as shown in FIG. 18 , in the radial cutting process, the focusing position starts to move along the first straight line, i.e., line M3a, from the position of the acceleration section separated from the object 100. At this time, the irradiation of the laser light L1 from the laser processing head 10A is stopped (OFF). The acceleration section is an auxiliary section that can make the moving speed of the focusing position constant. At the same time, the measurement data when the θ position is at 9 o'clock is read from the control unit 9 or the circuit unit 19. The driving unit 18 is driven by the control signal of the driving unit 18 as the measurement data, so that the focusing unit 14 moves toward the first initial position. The first initial position corresponds to the Z-direction position of the focusing unit 14 when the focusing position is at the θ position at 9 o'clock on the line M2 during the trimming process. After the focusing position enters the object 100 and passes the bevel portion, the irradiation of the laser light L1 from the laser processing head 10A starts (ON).

Furthermore, FIG. 18 shows various states when the light-converging position is moved in the Y direction and when viewed from the X direction, the light-converging position is located on the outside and inside of the object 100. The left and right directions in the figure correspond to the light-converging position. The same applies to FIG. 19 to FIG. 22. When the light-converging position is located at the object 100, the irradiation of the laser light L1 can be set to ON. However, in order to suppress the erosion at the bevel portion, the irradiation of the laser light L1 is set to OFF when the light-converging position is located at the bevel portion.

Next, the focusing position is moved along the line M3a. During this period, the control signal of the driving unit 18 is maintained by the circuit unit 19 with the measurement data when the θ position is at the 9 o'clock direction, and the position of the focusing unit 14 in the Z direction is maintained at the first initial position. Hereinafter, maintaining the position of the focusing unit 14 in the Z direction is also referred to as [AF fixing]. When the focusing position reaches the radial center of the removal area E, in order to make the voltage value obtained by the distance measurement sensor 36 become the reference voltage value for radial cutting processing, the driving unit 18 is driven by the circuit unit 19. In this way, AF tracking of driving the focusing unit 14 in a manner of tracking the displacement of the laser light incident surface is started. In Fig. 18, the area from the start of the movement of the focusing position to the start of AF tracking is the initial position holding area, and the area after the start of AF tracking is the tracking area. When the focusing position enters the effective area R, the irradiation of the laser light L1 from the laser processing head 10A is turned off.

Then, the focusing position is continuously moved in this state, and the focusing position is withdrawn from the inside to the outside of the object 100 along the line M3b. At this time, at the time point when the focusing position enters the removal area E, the irradiation of the laser light L1 from the laser processing head 10A is turned on, and AF fixation is started by the driver 18. In this AF fixation, the measurement data when the θ position is at the 3 o'clock direction is read from the control unit 9 or the circuit unit 19, and the driver 18 is driven by the circuit unit 19 using the control signal of the driver 18 as the measurement data, and the Z direction position of the focusing unit 14 is maintained. At the time point before the focusing position is about to withdraw from the object 100, the irradiation of the laser light L1 from the laser processing head 10A is turned off. Furthermore, the AF fixation control signal here may be a control signal value at the time of AF tracking just before the AF fixation is started, instead of the measurement data when the θ position is at the 3 o'clock direction.

Next, the stage 107 is rotated 90°, and the focusing position is moved along the second straight line, i.e., line M3c, from the position separating from the object 100 in the acceleration zone. At this time, the irradiation of the laser light L1 from the laser processing head 10A is stopped (OFF). At the same time, the measurement data when the θ position is at the 6 o'clock direction is read from the control unit 9 or the circuit unit 19. The driving unit 18 is driven by the control signal of the driving unit 18 as the measurement data, so that the focusing unit 14 moves toward the second initial position. The second initial position corresponds to the Z-direction position of the focusing unit 14 when the focusing position is at the θ position at the 6 o'clock direction of the line M2 during the trimming process. At the time point just after the focusing position enters the object 100, the irradiation of the laser light L1 from the laser processing head 10A is turned off. Then, the focusing position is moved along the line M3a, and the position of the focusing unit 14 is fixed by AF at the second initial position. When the focusing position reaches the radial center of the removal area E, AF tracking is started. At the time point when the focusing position enters the effective area R, the irradiation of the laser light L1 from the laser processing head 10A is turned off.

Then, the focusing position is continuously moved in this state, and the focusing position is withdrawn from the inside to the outside of the object 100 along the line M3d. At this time, at the time point when the focusing position enters the removal area E, the irradiation of the laser light L1 from the laser processing head 10A is turned on, and AF fixation is started. In this AF fixation, the measurement data when the θ position is at the 12 o'clock direction is read from the control unit 9 or the circuit unit 19, and the circuit unit 19 drives the drive unit 18 using the control signal of the drive unit 18 as the measurement data, and maintains the position of the focusing unit 14 in the Z direction. At the time point before the focusing position is about to withdraw from the object 100, the irradiation of the laser light L1 from the laser processing head 10A is turned off. Furthermore, the AF fixation control signal here may also be a control signal value at the time of AF tracking just before the AF fixation is started, instead of the measurement data when the θ position is at the 12 o'clock direction.

As described above, in the laser processing device 101 and the laser processing method of the present embodiment, when performing the radial cutting treatment and the radial cutting process, before the focusing position enters the inside of the object 100 from the outside, the focusing portion 14 is moved to the initial position according to the measurement data obtained in the radial cutting treatment and the radial cutting process by the driving portion 18. In this way, at a time point such as just after entering, the overshoot (exceeding the target value) generated in the control signal input to the driving portion 18 can be suppressed compared to the case where such an initial position is not considered. The tracking error (the error when the position of the focusing portion 14 in the Z direction is offset from the position that tracks the displacement of the laser light incident surface) can be reduced. That is, according to this embodiment, it is possible to suppress the reduction in the accuracy of the displacement of the laser light incident surface in the tracking operation.

In addition, the height setting performed after the trimming process and before the radial cutting process can be omitted, which can achieve a technique improvement (shortening of the operation time). In radial cutting, the processing area is extremely short, and the tracking error is not fully eliminated when advancing to the focusing position of the object 100, that is, passing through the processing area. Therefore, in radial cutting, the influence of the tracking error is extremely large. In this case, there is a possibility of undivided or poor quality (cracks or breaks) occurring later. Therefore, the effect of reducing the accuracy of the displacement of the laser light incident surface due to the tracking action can be suppressed, which is particularly effective in radial cutting.

In the laser processing device 101 and the laser processing method of the present embodiment, the control unit 9 forms a first modified area 41 along a line M2 around the periphery of the object 100 in the trimming process, and forms a second modified area 42 in the removal area E along a line M3 intersecting the line M2 in the radial cutting process. In this case, the removal area E of the object 100 can be cut off and removed.

In the laser processing device 101 and the laser processing method of the present embodiment, the initial position is based on the position of the measured data, which is the measured data on the displacement of the intersection position of the lines M2 and M3 on the laser light incident surface. In this way, when the removal area E of the object 100 is cut off and removed, the reduction in the accuracy of the displacement of the laser light incident surface by the tracking action can be further suppressed.

In the laser processing device 101 and the laser processing method of the present embodiment, the control unit 9 moves the focusing unit 14 along the line M2 during the trimming process, and drives the focusing unit 14 by the driving unit 18 in a manner that tracks the displacement of the laser light incident surface. At this time, the control signal value of the driving unit 18 when the focusing unit 14 is driven by the driving unit 18 in order to track the displacement of the laser light incident surface is used as measurement data, and is associated with the position information and stored. The control unit 9 reads the control signal value when tracking the displacement of the intersection position of the line M2 and the line M3 in the trimming process during the radial cutting process, and moves the focusing unit 14 along the line M3a so that the focusing position enters the inside from the outside of the object 100, and forms the second modified area 42 in the removal area E. Moreover, before the focusing position enters the inside from the outside of the object 100 or when it enters the inside, the driving unit 18 is controlled by the read control signal value to move the focusing unit 14 toward the first initial position. The control unit 9 reads the control signal value when the intersection position of the tracking line M2 and the line M3c is displaced in the trimming process, and moves the focusing unit 14 along the line M3c so that the focusing position enters the inside from the outside of the object 100, and forms the second modified area 42 in the removal area E. In addition, before or when the focusing position enters the inside from the outside of the object 100, the driving unit is controlled by the read control signal value to move the focusing unit 14 to the second initial position. In this way, in the trimming process of cutting and removing the removal area E of the object 100, the reduction in the accuracy of the displacement of the laser light incident surface by the tracking action can be further and specifically suppressed.

In the laser processing device 101 and the laser processing method of the present embodiment, the control unit 9 drives the focusing unit 14 to follow the displacement of the laser light incident surface by the driving unit 18 after the focusing position is located at the removal area E after the focusing unit 14 is moved to the initial position during the radiation cutting process. Even in this manner, even if the focusing unit is driven to follow the displacement of the laser light incident surface in the removal area E, the reduction in the accuracy of the displacement of the laser light incident surface due to the following operation can be suppressed.

In the laser processing device 101 and the laser processing method of the present embodiment, the distance measuring sensor 36 is used to irradiate the distance measuring laser light to the object 100 and detect the information about the reflected light of the distance measuring laser light reflected from the laser light incident surface. In this way, the distance measuring laser light can be used to make the focusing unit 14 track the displacement of the laser light incident surface.

Furthermore, the AF fixation of the present embodiment includes making the position of the light focusing unit 14 in the Z direction movable and maintained within a certain range, and is not limited to completely fixing the position of the light focusing unit 14 in the Z direction by the driving unit 18. That is, the AF fixation of the present embodiment is not limited to making the control signal of the driving unit 18 a certain control signal value. For example, as shown in FIG. 19, in the AF fixation of the present embodiment, the control signal value of the driving unit 18 is made to be a control signal value composed of the signal value of the measurement data during the trimming process and the signal value of the smoothly changing signal. Even in this case, the reduction in the accuracy of the displacement of the laser light incident surface by the tracking action can be suppressed.

As another example, as shown in FIG. 20, in the AF fixation of the present embodiment, the focusing unit 14 can be smoothly moved from the height setting position or other holding position to the vicinity of the initial position. That is, in the AF fixation of the present embodiment, the control signal value of the driving unit 18 can be made a control signal value that increases linearly toward the measurement data during the trimming process. Furthermore, in this case, it is not limited to a control signal value that increases linearly, and it can be a control signal value that decreases linearly or a control signal value that changes in a curved manner. Even in this case, the reduction in the accuracy of the displacement of the laser light incident surface by the tracking action can be suppressed.

In the present embodiment, the control unit 9 may keep the focusing unit 14 at the initial position by the driving unit 18 after the focusing unit 14 is moved to the initial position by the radiation cutting process and the focusing position is located in the removal area E. For example, as shown in FIG. 21 , the AF is fixed while the focusing position is located in the removal area E, and the AF tracking is performed just after the focusing position enters the effective area R. Even in this manner, when the focusing unit 14 is kept at the initial position in the removal area E, the reduction in the accuracy of the displacement of the laser light incident surface by the tracking action can be suppressed. In this case, it is very effective when the removal area E is very narrow. Furthermore, even after the focusing position enters the effective area R, the AF fixing state may be set without performing AF tracking.

In this embodiment, the control unit 9 may drive the focusing unit 14 by the driving unit 18 to track the displacement of the laser light incident surface after the focusing position just enters the object 100 after the focusing unit 14 moves toward the initial position during the radiation cutting process. For example, as shown in FIG. 22 , AF tracking may be started immediately after the focusing position enters the object 100. The start of AF tracking may be performed based on the coordinates of the focusing position or based on the amount of reflected light received by the distance measuring sensor 36. Even in this case, the reduction in the accuracy of the displacement of the laser light incident surface due to the tracking operation may be suppressed. Furthermore, even if a large overshoot occurs in the control signal of the driving unit 18 due to the influence of the bevel portion of the outer edge of the object 100, AF tracking may be started just after the object 100 enters the focusing position and passes the bevel portion.

In the present embodiment, with respect to the displacement of the laser light incident surface of the object 100 supported on the mounting table 107, in the case where the unevenness and inclination of the supporting surface 107a are dominant (the flatness of the laser light incident surface itself is higher), when laser processing is performed on a plurality of objects 100, it is also possible to obtain measurement data when the first first object 100 is trimmed, and use this measurement data when trimming the second and subsequent objects 100.

In this embodiment, at least one of the reference voltage value for trimming and the reference voltage value for radial cutting can be corrected by the height offset function. In the height offset function, for example, when the distance measurement sensor 36 is a coaxial sensor, the reference voltage value for trimming and the reference voltage value for radial cutting can be pre-associated with the center value of the control signal of the drive unit 18, and each reference voltage value can be corrected in response to the control signal when AF tracking is performed. In the height offset function, for example, when the distance measuring sensor 36 is a sensor of a different axis, the voltage value corresponding to the difference between the Z-direction position of the focusing position when the first modified area 41 of the first row is formed by trimming processing and the Z-direction position of the focusing position when the second modified area 42 of the first row is formed by radial cutting processing can be added to the reference voltage value for radial cutting processing.

FIG23 is a graph showing the accuracy of the tracking action of the radial cutting process to the displacement of the laser light incident surface in the first comparative example. In FIG23, the horizontal axis shows the distance along the line M3 of the focusing position from the periphery of the object 100. On the horizontal axis, the periphery of the object 100 is set to 0, and the inside of the object 100 is set to positive. The vertical axis shows the relative position in the Z direction when the height setting position is set to 0, that is, the relative height. D1 is the data of the relative height corresponding to the current position of the actual focusing part 14, D2 is the data of the relative height corresponding to the control signal value of the drive part 18, and D3 is the data of the relative height corresponding to the displacement of the laser light incident surface. The description in FIG. 23 is the same in FIG. 24 to FIG. 26 .

In the radial cutting process of the first comparative example, AF is fixed at the height setting position before the focusing position enters the removal area E, and AF tracking is started at the time point when the focusing position enters the removal area E. As shown in FIG. 23 , it can be seen that in the radial cutting process of the first comparative example, there is an overshoot of the control signal value that greatly exceeds the displacement of the laser light incident surface at the edge of the object 100. In addition, it can be seen that the control signal value is delayed at the current position of the focusing part 14, and a difference of about 3μm is generated in relative height at a distance of 0mm~10mm. It can be seen that in the removal area E, the tracking error is large.

FIG24 is a graph showing the accuracy of the tracking action of the radial cutting process to the displacement of the laser light incident surface in the first embodiment. The radial cutting process of the first embodiment is one aspect of the present invention described above. In the radial cutting process of the first embodiment, before the focusing position enters the removal area E, AF fixing is performed at the initial position based on the measurement data obtained by the trimming process, and AF tracking is started at the time point of entering the removal area E. As shown in FIG24, in the radial cutting process of the first embodiment, it can be seen that even if AF tracking is performed, overshoot is greatly reduced. It can be seen that in the removal area E, the tracking error can be suppressed.

FIG. 25 is a graph showing the accuracy of the tracking action of the radial cutting process for the displacement of the laser light incident surface in the second comparative example. In the radial cutting process of the second comparative example, while the focusing position passes through the removal area E and is located inside the object 100, AF fixing is performed at the height setting position, and AF tracking is started at a later time point. As shown in FIG. 25, in the radial cutting process of the second comparative example, the tracking error is still large in the removal area E.

FIG. 26 is a graph showing the accuracy of the tracking action of the radial cutting process to the displacement of the laser light incident surface in the second embodiment. The radial cutting process of the second embodiment is one aspect of the present invention. In the radial cutting process of the second embodiment, the AF is fixed at the initial position based on the measurement data obtained by the trimming process until it is located inside the object 100 at the focusing position, and the AF tracking is started at a later time point. As shown in FIG. 26, it is known that in the radial cutting process of the second embodiment, the tracking error can be suppressed by removing the area E.

As mentioned above, one aspect of the present invention is not limited to the aforementioned implementation forms.

In the above-mentioned embodiments and modifications, the radial cutting process of the radial cutting process and the radial cutting process as the second treatment and the second process is described as an example, but it is not limited to this. For example, after the trimming process, the cutting process of forming the modified area inside the effective area R can also be performed. In this case, the second treatment and the second process correspond to the treatment and process for realizing the cutting process.

Specifically, as shown in FIG. 27(a) and FIG. 27(b), the control unit 9 forms the second modified region 42 in the effective region R (the inner portion of the object 100 that is further inner than the first modified region 41 when viewed from the laser light incident surface) along a straight line M4 that intersects the line M2 (see FIG. 15(a)) in the second process of realizing the cutting process. The lines M4 are provided in the object 100 in a plurality. The plurality of lines M4 are provided in a grid shape at least in the effective region R. In this case, the second modified region 42 can be formed in the effective region R of the object 100 so that the cracks formed from the second modified region 42 are not easily extended toward the removal region E of the object 100.

In the second processing in this case, the initial position is based on the position of the measured data of the displacement of the intersection position of the line M3 of the laser light incident surface and the line M4 when the focusing position is moved along the line M4. In this way, when the second modified area 42 is formed in such a way that the cracks from the second modified area 42 are not easy to extend toward the removal area E, the reduction in the accuracy of the displacement of the laser light incident surface by the tracking operation can be further suppressed.

In the example shown in FIG. 27(a) and FIG. 27(b), when the second modified area 42 is formed, when the focusing position of the laser light L1 is located at the outer edge, the irradiation of the laser light L1 is set to OFF. However, the OFF interval is set according to the range of the divisible object 100, so it can be determined without being affected by the position of the first modified area 41 in the trimming process. Furthermore, in this case, the irradiation of the laser light L1 may not be set to OFF. As shown in the figure, when the second modified area 42 exceeds the range of the first modified area 41 in the trimming process and extends outward, it helps to divide the object 100 and stabilize the second modified area 42 in the effective area R. The processing of the example shown in the figure is mainly effective for processing thinner objects 100.

Alternatively, after the trimming process, for example, instead of performing the radial cutting process, a stripping process may be performed. In this case, the second treatment and the second process correspond to the treatment and process for realizing the stripping process. Specifically, as shown in Figures 28(a) and 28(b), the control unit 9 forms a second modified area 42 along the imaginary surface M1 (refer to the line M5 in Figure 10(b)) with the inside of the object 100 in the second treatment for realizing the stripping process. The line M5 is set to the effective area R. The line M5 extends into a spiral shape centered on the center position of the object 100. In this case, the second treatment is initially The expected position is the measurement data of the displacement of the θ position at the start of the second treatment irradiation on the line M2 of the laser light incident surface. The θ position at the start of the second treatment irradiation is the θ position around the θ axis (here around the rotation axis C in FIG. 9 ) of the laser light incident surface where the laser light L1 is irradiated at the start of the second treatment. In this way, the reduction in the accuracy of the displacement of the laser light incident surface by the tracking action can be further suppressed in the peeling process.

In the aforementioned embodiments and modifications, the back side 100b of the object 100 is used as the laser light incident surface, but the surface 100a of the object 100 may also be used as the laser light incident surface. In the aforementioned embodiments and modifications, the modified region 4 may also be, for example, a crystallization region, a recrystallization region, or an absorption region formed inside the object 100. The crystallization region is a region that maintains the structure of the object 100 before processing. The recrystallization region is a region that solidifies as a single crystal or multiple crystals when solidifying after temporary evaporation, plasma formation, or melting. The absorption region is a region that exerts an absorption effect to collect and capture impurities such as heavy metals, and may be formed continuously or intermittently. Furthermore, for example, a laser processing device may be applicable to processing such as stripping plasma.

In the above-mentioned embodiments and modifications, the moving mechanism may move at least one of the mounting table 107 and the laser processing head 10A. In the above-mentioned embodiments and modifications, the driving unit 18 may drive at least one of the mounting table 107 and the focusing unit 14 along the Z direction.

In the above-mentioned embodiments and modifications, the position of the light-concentrating portion 14 along the Z direction is moved toward the initial position by the driving portion 18 before the light-concentrating portion enters the object 100 from the outside. However, the position of the light-concentrating portion 14 along the Z direction is moved toward the initial position by the driving portion 18 when the light-concentrating portion enters the object 100 from the outside. When the light-concentrating portion enters the object 100 includes the time point when the light-concentrating portion enters the object 100 and the time point substantially the same as the time point.

In the above-mentioned embodiments and modifications, the θ position is used as the position information, but at least one of the time and coordinate information from the start of the laser processing can be used as the position information instead of the θ position or in addition. The position information is information that can be used to know the position of the circumference of the object 100. In the above-mentioned embodiments and modifications, the height setting performed after the trimming process and before the radial cutting process is omitted, but the height setting may not be omitted.

In the aforementioned embodiments and variations, the control signal (voltage value) of the driving unit 18 is obtained as the measurement data, but the measurement data is not particularly limited and may be the absolute position of the focusing unit 14 in the Z direction or the relative position to the position when the height is set.

In the above-mentioned embodiments and variations, when radial cutting processing is performed from a predetermined θ direction to the object 100, for example, the measurement data used when the focusing unit 14 is located at the initial position may be at least one of the following. (1) Measurement data of the θ position in the predetermined θ direction. (2) The average value of measurement data of a plurality of sampling positions before, after, or before and after the θ position in the predetermined θ direction. (3) The measurement data is a graph approximating the convexity and concavity on the circumference of the object 100 or data converted into an equation. (4) Data of the concavity and convexity of the mounting table 107.

In the above-mentioned embodiments and modifications, during trimming, AF tracking is performed while irradiating the laser light L1 to obtain measurement data, but it is also possible to perform AF tracking separately without irradiating the laser light L1 to obtain measurement data. In the above-mentioned embodiments and modifications, during radial cutting, if the above-mentioned overshoot can be suppressed, after reading the measurement data obtained during trimming, the drive unit 18 can be controlled based on the value of adding or subtracting a predetermined value from the measurement data.

The structures of the aforementioned embodiments and modifications are not limited to the aforementioned materials and shapes, and can be applied to various materials and shapes. In addition, the structures of the aforementioned embodiments and modifications can be arbitrarily applied to the structures of other embodiments or modifications.

1,101: Laser processing device 4: Modified area 41: First modified area (modified area) 42: Second modified area (modified area) 5,6,200,300,400: Moving mechanism 7: Support unit 9: Control unit 10A,10B,10C,10D: Laser processing head (irradiation unit) 14: Focusing unit (focusing lens) 18: Driving unit 19: Circuit unit (measurement data acquisition unit) 36: Distance measurement sensor (measurement data acquisition unit) 55,65,66,305,306,405,406: Mounting unit 100: Object 100b: Back side (laser light incident side) 106A: 1st Z-axis track (moving mechanism) 107: loading platform (supporting part) 107a: supporting surface 108: Y-axis track (moving mechanism) E: removal area (peripheral part) L1, L2: laser light (laser light) M1: imaginary surface M2: line (annular line) M3: line (straight line) M3a: line (1st straight line) M3c: line (2nd straight line) M4: line (straight line) P1: focusing position R: effective area (inner area)

[FIG. 1] is an oblique view of a laser processing device of an embodiment. [FIG. 2] is a front view of a portion of the laser processing device shown in FIG. 1. [FIG. 3] is a front view of a laser processing head of the laser processing device shown in FIG. 1. [FIG. 4] is a side view of the laser processing head shown in FIG. 3. [FIG. 5] is a configuration diagram of an optical system of the laser processing head shown in FIG. 3. [FIG. 6] is a configuration diagram of an optical system of a laser processing head of a modified example. [FIG. 7] is a front view of a portion of a laser processing device of a modified example. [FIG. 8] is an oblique view of a laser processing device of a modified example. [FIG. 9] is a plan view showing a schematic structure of the laser processing device of the first embodiment. [FIG. 10(a)] is a plan view showing an example of an object. [Fig. 10(b)] is a side view of the object shown in Fig. 10(a). [Fig. 11(a)] is a side view of the object for explaining the laser processing of the implementation form. [Fig. 11(b)] is a plan view of the object following Fig. 11(a). [Fig. 11(c)] is a side view of the object shown in Fig. 11(b). [Fig. 12(a)] is a side view of the object following Fig. 11(b). [Fig. 12(b)] is a plan view of the object following Fig. 12(a). [Fig. 13(a)] is a plan view of the object following Fig. 12(b). [Fig. 13(b)] is a side view of the object shown in Fig. 13(a). [Figure 13(c)] is a side view of the object following Figure 13(b). [Figure 14(a)] is a plan view of the object following Figure 13(c). [Figure 14(b)] is a side view of the object shown in Figure 14(a). [Figure 14(c)] is a side view of the object following Figure 14(a). [Figure 14(d)] is a side view of the object following Figure 14(c). [Figure 15(a)] is a plan view of the object for explaining trimming. [Figure 15(b)] is a plan view of the object following Figure 15(a). [Figure 16] is a graph showing an example of measurement data associated with position information and acquired. [Figure 17] is a plan view of an object for explaining radial cutting. [Figure 18] is a diagram showing examples of various states when the focusing position is located on the outside and inside of the object during radial cutting. [Figure 19] is a diagram showing other examples of various states when the focusing position is located on the outside and inside of the object during radial cutting. [Figure 20] is a diagram showing other examples of various states when the focusing position is located on the outside and inside of the object during radial cutting. [Figure 21] is a diagram showing other examples of various states when the focusing position is located on the outside and inside of the object during radial cutting. [Figure 22] is a diagram showing other examples of various states when the focusing position is located on the outside and inside of the object during radial cutting. [Figure 23] is a graph showing the accuracy of the displacement of the laser light incident surface by the tracking action of the radial cutting process in the first comparative example. [Figure 24] is a graph showing the accuracy of the displacement of the laser light incident surface by the tracking action of the radial cutting process in the first embodiment. [Figure 25] is a graph showing the accuracy of the displacement of the laser light incident surface by the tracking action of the radial cutting process in the second comparative example. [Figure 26] is a graph showing the accuracy of the displacement of the laser light incident surface by the tracking action of the radial cutting process in the second embodiment. [Figure 27(a)] is a plan view of an object for explaining the cutting process. [Figure 27(b)] is a plan view of the object subsequent to Figure 27(a). [Figure 28(a)] is a plan view of an object used to illustrate the peeling process. [Figure 28(b)] is a plan view showing the object after Figure 28(a).

9: Control Department

10A: Laser processing head (irradiation part)

14: Focusing part (focusing lens)

18: Drive unit

34: Reflective spatial light modulator

36: Distance measurement sensor (measurement data acquisition unit)

65: Installation Department

100: Object

100a: Surface

100b: Back side (laser light incident side)

101: Laser processing equipment

106A: 1st Z axis track (moving mechanism)

107: Loading table (supporting part)

107a: Support surface

108: Y-axis track (moving mechanism)

110: Camera Department

111:GUI

AC: Alignment camera

C: Rotation axis

E: Remove area (peripheral part)

IR: Imaging unit

M3: Line (straight line)

R: Effective area (inner area)

Claims (14)

A laser processing device forms a modified area inside an object by irradiating the object with laser light, and is characterized by comprising: a support portion for supporting the object; an irradiation portion for irradiating the object with the laser light through a focusing lens; a moving mechanism for moving at least one of the support portion and the irradiation portion to move the focusing position of the laser light; a driving portion for driving at least one of the support portion and the focusing lens along the optical axis direction of the focusing lens; a measurement data acquisition portion for acquiring measurement data on at least one of the displacement of the laser light incident surface of the object on which the laser light is incident and the displacement of the support surface of the support portion supporting the object; and A control unit controls the irradiation unit, the moving mechanism and the driving unit. The control unit performs: a first process, wherein at least one of the support unit and the irradiation unit is moved inwardly from the periphery of the object so that the focusing position moves along the periphery to form a first modified area inside the object along the periphery; and a second process, wherein after performing the first process, at least one of the support unit and the irradiation unit is moved so that the focusing position moves from the outside of the object to the inside to form a second modified area inside the object. The measurement data acquisition unit associates the measurement data with the position information about the position of the object in the first process and acquires the measurement data. The control unit moves the position along the optical axis direction of at least one of the support unit and the focusing lens by the driving unit toward the initial position according to the measurement data obtained in the first processing in the second processing, before or when the focusing position enters the inside of the object from the outside. The control unit forms the first modified area along the annular line around the periphery of the object in the first processing. In the second processing, the second modified area is formed in the peripheral portion of the object from the periphery to the first modified area when viewed from the laser light incident surface along the straight line intersecting the annular line. The aforementioned initial position is based on the position of the aforementioned measurement data, which is the measurement data on the displacement of the intersection position of the aforementioned ring line and the aforementioned straight line before the aforementioned laser light incident surface. A laser processing device as claimed in claim 1, wherein, the control unit moves at least one of the support unit and the irradiation unit in the first processing so that the focusing position moves along the periphery, and drives at least one of the support unit and the focusing lens by the drive unit in a manner that tracks the displacement of the laser light incident surface, the measurement data acquisition unit, in the first processing, uses the control signal value of the drive unit in the case where the drive unit drives at least one of the support unit and the focusing lens in order to track the displacement of the laser light incident surface as the measurement data, and associates it with the position information and stores it, the control unit, in the second processing, The control signal value mentioned above is read when the first processing follows the displacement of the intersection position of the annular line and the first straight line. Move at least one of the support part and the irradiation part along the first straight line so that the focusing position enters the inside from the outside of the object and the second modified area is formed in the peripheral part. Moreover, before or when the focusing position enters the inside from the outside of the object, the driving part is controlled by the control signal value read so that at least one of the support part and the focusing lens moves toward the first initial position. Read the control signal value mentioned above when the first processing follows the displacement of the intersection position of the annular line and the second straight line. At least one of the support part and the irradiation part is moved along the second straight line, so that the focusing position enters the inside of the object from the outside, and the second modified area is formed in the peripheral part. Moreover, before or when the focusing position enters the inside of the object from the outside, the driving part is controlled by the read control signal value, so that at least one of the support part and the focusing lens is moved to the second initial position. A laser processing device forms a modified area inside an object by irradiating the object with laser light, and is characterized by comprising: a support portion for supporting the object; an irradiation portion for irradiating the object with the laser light through a focusing lens; a moving mechanism for moving at least one of the support portion and the irradiation portion to move the focusing position of the laser light; a driving portion for driving at least one of the support portion and the focusing lens along the optical axis direction of the focusing lens; a measurement data acquisition portion for acquiring measurement data on at least one of the displacement of the laser light incident surface of the object on which the laser light is incident and the displacement of the support surface of the support portion supporting the object; and A control unit controls the irradiation unit, the moving mechanism and the driving unit. The control unit performs: a first process, wherein at least one of the support unit and the irradiation unit is moved inwardly from the periphery of the object so that the focusing position moves along the periphery to form a first modified area inside the object along the periphery; and a second process, wherein after performing the first process, at least one of the support unit and the irradiation unit is moved so that the focusing position moves from the outside of the object to the inside to form a second modified area inside the object. The measurement data acquisition unit associates the measurement data with the position information about the position of the object in the first process and acquires the measurement data. The control unit moves the position along the optical axis direction of at least one of the support unit and the focusing lens by the driving unit toward the initial position according to the measurement data obtained in the first processing in the second processing, before or when the focusing position enters the inside of the object from the outside. The control unit forms the first modified area along the annular line around the periphery of the object in the first processing. In the second processing, the second modified area is formed in the inner part of the object more inner than the first modified area when viewed from the laser light incident surface along the straight line intersecting the annular line. The inner part more inner than the first modified area is the effective area. The aforementioned straight lines are provided in a plurality in the aforementioned object, and the aforementioned straight lines are provided in a grid pattern in the aforementioned effective area. The laser processing device of claim 3, wherein the initial position is based on the position of the measurement data, which is the measurement data on the displacement of the intersection position of the annular line and the straight line before the laser light incident surface. A laser processing device forms a modified area inside an object by irradiating the object with laser light, and is characterized by comprising: a support portion for supporting the object; an irradiation portion for irradiating the object with the laser light through a focusing lens; a moving mechanism for moving at least one of the support portion and the irradiation portion to move the focusing position of the laser light; a driving portion for driving at least one of the support portion and the focusing lens along the optical axis direction of the focusing lens; a measurement data acquisition portion for acquiring measurement data on at least one of the displacement of the laser light incident surface of the object on which the laser light is incident and the displacement of the support surface of the support portion supporting the object; and A control unit controls the irradiation unit, the moving mechanism and the driving unit. The control unit performs: a first process, wherein at least one of the support unit and the irradiation unit is moved inwardly from the periphery of the object so that the focusing position moves along the periphery to form a first modified area inside the object along the periphery; and a second process, wherein after performing the first process, at least one of the support unit and the irradiation unit is moved so that the focusing position moves from the outside of the object to the inside to form a second modified area inside the object. The measurement data acquisition unit associates the measurement data with the position information about the position of the object in the first process and acquires the measurement data. The control unit moves the position along the optical axis direction of at least one of the support unit and the focusing lens by the driving unit toward the initial position according to the measurement data obtained in the first processing, before or when the focusing position enters the inside of the object from the outside, in the second processing. The control unit forms the first modified area along the annular line around the periphery of the object in the first processing, forms the second modified area along the imaginary surface inside the object in the second processing, forms the second modified area along the line on the peeling predetermined surface inside the object (i.e., the surface opposite to the laser light incident surface) in the second processing. A laser processing device as claimed in claim 5, wherein, the control unit uses the θ position around the θ axis of the laser light incident surface before the laser light is irradiated at the start of the second processing as the θ position for irradiation start of the second processing, the initial position is a position based on the measurement data, which is the measurement data regarding the displacement of the θ position for irradiation start of the second processing of the annular line before the laser light incident surface. A laser processing device as claimed in any one of claims 1 to 6, wherein, the control unit drives at least one of the support unit and the focusing lens to follow the displacement of the laser light incident surface when the focusing position is located at the peripheral portion from the periphery of the object to the first modified area when viewed from the laser light incident surface in the second process after the support unit and the focusing lens are moved toward the initial position. A laser processing device forms a modified area inside an object by irradiating the object with laser light, and is characterized by comprising: a support portion for supporting the object; an irradiation portion for irradiating the object with the laser light through a focusing lens; a moving mechanism for moving at least one of the support portion and the irradiation portion to move the focusing position of the laser light; a driving portion for driving at least one of the support portion and the focusing lens along the optical axis direction of the focusing lens; a measurement data acquisition portion for acquiring measurement data on at least one of the displacement of the laser light incident surface of the object on which the laser light is incident and the displacement of the support surface of the support portion supporting the object; and A control unit controls the irradiation unit, the moving mechanism and the driving unit. The control unit performs: a first process, wherein at least one of the support unit and the irradiation unit is moved inwardly from the periphery of the object so that the focusing position moves along the periphery to form a first modified area inside the object along the periphery; and a second process, wherein after performing the first process, at least one of the support unit and the irradiation unit is moved so that the focusing position moves from the outside of the object to the inside to form a second modified area inside the object. The measurement data acquisition unit associates the measurement data with the position information about the position of the object in the first process and acquires the measurement data. The control unit moves the position of at least one of the support unit and the focusing lens along the optical axis direction by the driving unit to the initial position according to the measurement data obtained in the first processing before or when the focusing position enters the interior of the object from the exterior. The control unit moves at least one of the support unit and the focusing lens to the initial position in the second processing. When the focusing position is located at the peripheral portion from the periphery of the object to the first modified region when viewed from the laser light incident surface, the driving unit drives at least one of the support unit and the focusing lens to track the displacement of the laser light incident surface. A laser processing device as claimed in any one of claims 1 to 6, wherein, the control unit, in the second process, moves at least one of the support unit and the focusing lens toward the initial position, and when the focusing position is located in the peripheral portion from the periphery of the object to the first modified area when viewed from the laser light incident surface, at least one of the support unit and the focusing lens is maintained at the initial position by the driving unit. A laser processing device as claimed in any one of claims 1 to 6 and 8, wherein the measurement data acquisition unit has a sensor that irradiates the object with measurement light and detects information about reflected light of the measurement light reflected from the laser light incident surface. A laser processing method is to form a modified area inside the object by irradiating the object with laser light, and is characterized by having: A first process, which is to move at least one of a support portion supporting the object and an irradiation portion irradiating the object with the laser light through a focusing lens, further inward than the periphery of the object, so that the focusing position of the laser light moves along the periphery, thereby forming a first modified area inside the object along the periphery; and A second process, which is to move at least one of the support portion and the irradiation portion so that the focusing position moves from the outside of the object to the inside, thereby forming a second modified area inside the object after performing the first process. In the first process, The displacement of the laser light incident surface of the aforementioned object on which the aforementioned laser light is incident and the displacement of the supporting surface of the aforementioned supporting portion supporting the aforementioned object are correlated with the position information about the position of the aforementioned object and obtained. In the aforementioned second process, before or when the aforementioned focusing position enters the interior from the outside of the aforementioned object, the position along the optical axis direction of at least one of the aforementioned supporting portion and the aforementioned focusing lens by the driving portion is moved toward the initial position according to the aforementioned measurement data obtained in the aforementioned first process. In the aforementioned first process, the aforementioned first modified area is formed along a ring line around the circumference of the aforementioned object. In the aforementioned second process, along the straight line intersecting the aforementioned ring line, when viewed from the aforementioned laser light incident surface, the aforementioned second modified area is formed in the peripheral portion of the aforementioned object from the periphery to the aforementioned first modified area. The aforementioned initial position is based on the position of the aforementioned measurement data, which is the measurement data on the displacement of the intersection position of the aforementioned ring line and the aforementioned straight line before the aforementioned laser light incident surface. A laser processing method is to form a modified area inside the object by irradiating the object with laser light, and is characterized by having: A first process, which is to move at least one of a support portion supporting the object and an irradiation portion irradiating the object with the laser light through a focusing lens, further inward than the periphery of the object, so that the focusing position of the laser light moves along the periphery, thereby forming a first modified area inside the object along the periphery; and A second process, which is to move at least one of the support portion and the irradiation portion so that the focusing position moves from the outside of the object to the inside, thereby forming a second modified area inside the object after performing the first process. In the first process, The displacement of the laser light incident surface of the aforementioned object on which the aforementioned laser light is incident and the displacement of the supporting surface of the aforementioned supporting portion supporting the aforementioned object are correlated with the position information about the position of the aforementioned object and obtained. In the aforementioned second process, before or when the aforementioned focusing position enters the interior of the aforementioned object from the exterior, the position along the optical axis direction of at least one of the aforementioned supporting portion and the aforementioned focusing lens through the aforementioned driving portion is moved toward the initial position according to the aforementioned measurement data obtained in the aforementioned first process. In the aforementioned first process, the aforementioned first modified area is formed along a ring line around the circumference of the aforementioned object. In the second process, along the straight line intersecting the annular line, when viewed from the laser light incident surface, the second modified area is formed in the inner part of the object which is inner than the first modified area. The inner part which is inner than the first modified area is the effective area. There are a plurality of straight lines in the object. The straight lines are arranged in a grid pattern in the effective area. A laser processing method is to form a modified area inside the object by irradiating the object with laser light, and is characterized by having: A first process, which is to move at least one of a support portion supporting the object and an irradiation portion irradiating the object with the laser light through a focusing lens, further inward than the periphery of the object, so that the focusing position of the laser light moves along the periphery, thereby forming a first modified area inside the object along the periphery; and A second process, which is to move at least one of the support portion and the irradiation portion so that the focusing position moves from the outside of the object to the inside, thereby forming a second modified area inside the object after performing the first process. In the first process, The displacement of the laser light incident surface of the aforementioned object on which the aforementioned laser light is incident and the displacement of the supporting surface of the aforementioned supporting portion supporting the aforementioned object are correlated with the position information about the position of the aforementioned object and obtained. In the aforementioned second process, before or when the aforementioned focusing position enters the interior of the aforementioned object from the exterior, the position along the optical axis direction of at least one of the aforementioned supporting portion and the aforementioned focusing lens through the aforementioned driving portion is moved toward the initial position according to the aforementioned measurement data obtained in the aforementioned first process. In the aforementioned first process, the aforementioned first modified region is formed along a ring line around the circumference of the aforementioned object. In the aforementioned second process, the aforementioned second modified region is formed along an imaginary surface inside the aforementioned object. In the aforementioned second process, the aforementioned second modified area is formed along a line on the predetermined peeling surface inside the aforementioned object (i.e., the surface opposite to the aforementioned laser light incident surface). A laser processing method is to form a modified area inside the object by irradiating the object with laser light, and is characterized by having: A first process, which is to move at least one of a support portion supporting the object and an irradiation portion irradiating the object with the laser light through a focusing lens, further inward than the periphery of the object, so that the focusing position of the laser light moves along the periphery, thereby forming a first modified area inside the object along the periphery; and A second process, which is to move at least one of the support portion and the irradiation portion so that the focusing position moves from the outside of the object to the inside, thereby forming a second modified area inside the object after performing the first process. In the first process, The displacement of the laser light incident surface of the aforementioned object on which the aforementioned laser light is incident and the displacement of the supporting surface of the aforementioned supporting portion supporting the aforementioned object are correlated with the position information about the position of the aforementioned object and obtained. In the aforementioned second process, before or when the aforementioned focusing position enters the interior of the aforementioned object from the exterior, the position along the optical axis direction of at least one of the aforementioned supporting portion and the aforementioned focusing lens through the aforementioned driving portion is moved toward the initial position according to the aforementioned measurement data obtained in the aforementioned first process. In the aforementioned second process, after at least one of the aforementioned support portion and the aforementioned focusing lens is moved toward the aforementioned initial position, when viewed from the aforementioned laser light incident surface, the aforementioned focusing position is located in the peripheral portion from the periphery of the aforementioned object to the aforementioned first modified area, and at least one of the aforementioned support portion and the aforementioned focusing lens is maintained at the initial position by the aforementioned driving portion.

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